Restore behaviour of not having test logs on stdout/stderr by default

With the refactoring to use global loggers, `logp` has changed behaviour and now tests that use a testing logger, like [`logptest.NewTestingLogger`](https://github.com/elastic/elastic-agent-libs/blob/main/logp/logptest/logptest.go). Making the output of `go test -v` pretty much unreadable, it is not possible to see the tests that are running and the time they took.

As an example, let's get Filebeat Filestream's tests, from Beats root:
```
cd filebeat/input/filestream
git checkout v9.0.0
go test -v -count=1
```
The output is a clear list of all the tests run and the time they took. It's 208 lines long.
output

```
% go test -v -count=1
=== RUN TestConfigValidate
=== RUN TestConfigValidate/paths_cannot_be_empty
--- PASS: TestConfigValidate (0.00s)
--- PASS: TestConfigValidate/paths_cannot_be_empty (0.00s)
=== RUN TestValidateInputIDs
=== RUN TestValidateInputIDs/empty_config
=== RUN TestValidateInputIDs/one_empty_ID_is_allowed
=== RUN TestValidateInputIDs/duplicated_empty_ID
=== RUN TestValidateInputIDs/duplicated_IDs
=== RUN TestValidateInputIDs/duplicated_IDs_and_empty_ID
=== RUN TestValidateInputIDs/only_unique_IDs
--- PASS: TestValidateInputIDs (0.00s)
--- PASS: TestValidateInputIDs/empty_config (0.00s)
--- PASS: TestValidateInputIDs/one_empty_ID_is_allowed (0.00s)
--- PASS: TestValidateInputIDs/duplicated_empty_ID (0.00s)
--- PASS: TestValidateInputIDs/duplicated_IDs (0.00s)
--- PASS: TestValidateInputIDs/duplicated_IDs_and_empty_ID (0.00s)
--- PASS: TestValidateInputIDs/only_unique_IDs (0.00s)
=== RUN TestCopyTruncateProspector_Create
=== RUN TestCopyTruncateProspector_Create/first_rotated_file,_when_rotated_file_not_exist
=== RUN TestCopyTruncateProspector_Create/one_new_file,_then_rotated
=== RUN TestCopyTruncateProspector_Create/one_new_file,_then_rotated_twice_in_order
=== RUN TestCopyTruncateProspector_Create/one_new_file,_then_rotated_twice_with_renaming
--- PASS: TestCopyTruncateProspector_Create (0.00s)
--- PASS: TestCopyTruncateProspector_Create/first_rotated_file,_when_rotated_file_not_exist (0.00s)
--- PASS: TestCopyTruncateProspector_Create/one_new_file,_then_rotated (0.00s)
--- PASS: TestCopyTruncateProspector_Create/one_new_file,_then_rotated_twice_in_order (0.00s)
--- PASS: TestCopyTruncateProspector_Create/one_new_file,_then_rotated_twice_with_renaming (0.00s)
=== RUN TestNumericSorter
=== RUN TestNumericSorter/one_fileinfo
=== RUN TestNumericSorter/ordered_fileinfos
=== RUN TestNumericSorter/unordered_fileinfos
=== RUN TestNumericSorter/unordered_fileinfos_with_numbers_in_filename
--- PASS: TestNumericSorter (0.00s)
--- PASS: TestNumericSorter/one_fileinfo (0.00s)
--- PASS: TestNumericSorter/ordered_fileinfos (0.00s)
--- PASS: TestNumericSorter/unordered_fileinfos (0.00s)
--- PASS: TestNumericSorter/unordered_fileinfos_with_numbers_in_filename (0.00s)
=== RUN TestDateSorter
=== RUN TestDateSorter/one_fileinfo
=== RUN TestDateSorter/ordered_fileinfos
=== RUN TestDateSorter/unordered_fileinfos
--- PASS: TestDateSorter (0.00s)
--- PASS: TestDateSorter/one_fileinfo (0.00s)
--- PASS: TestDateSorter/ordered_fileinfos (0.00s)
--- PASS: TestDateSorter/unordered_fileinfos (0.00s)
=== RUN TestLogFileTimedClosing
=== RUN TestLogFileTimedClosing/read_from_file_and_close_on_EOF
=== RUN TestLogFileTimedClosing/read_from_file_and_close_inactive
=== RUN TestLogFileTimedClosing/read_from_file_and_close_after_interval
--- PASS: TestLogFileTimedClosing (5.04s)
--- PASS: TestLogFileTimedClosing/read_from_file_and_close_on_EOF (0.00s)
--- PASS: TestLogFileTimedClosing/read_from_file_and_close_inactive (2.00s)
--- PASS: TestLogFileTimedClosing/read_from_file_and_close_after_interval (3.04s)
=== RUN TestLogFileTruncated
--- PASS: TestLogFileTruncated (0.00s)
=== RUN TestFileWatcher
=== RUN TestFileWatcher/detects_a_new_file
=== RUN TestFileWatcher/detects_a_file_write
=== RUN TestFileWatcher/detects_a_file_rename
=== RUN TestFileWatcher/detects_a_file_truncate
=== RUN TestFileWatcher/emits_truncate_on_touch_when_resend_on_touch_is_enabled
=== RUN TestFileWatcher/detects_a_file_remove
=== RUN TestFileWatcher/propagates_a_fingerprints_for_a_new_file
=== RUN TestFileWatcher/does_not_emit_events_if_a_file_is_touched_and_resend_on_touch_is_disabled
=== RUN TestFileWatcher/does_not_emit_events_for_empty_files
=== RUN TestFileWatcher/does_not_emit_events_for_empty_files/issues_a_debug_message_in_logs
=== RUN TestFileWatcher/does_not_emit_events_for_empty_files/emits_a_create_event_once_something_is_written_to_the_empty_file
=== RUN TestFileWatcher/does_not_emit_an_event_for_a_fingerprint_collision
=== RUN TestFileWatcher/does_not_log_warnings_on_duplicate_globs_and_filters_out_duplicates
--- PASS: TestFileWatcher (1.65s)
--- PASS: TestFileWatcher/detects_a_new_file (0.00s)
--- PASS: TestFileWatcher/detects_a_file_write (0.10s)
--- PASS: TestFileWatcher/detects_a_file_rename (0.10s)
--- PASS: TestFileWatcher/detects_a_file_truncate (0.10s)
--- PASS: TestFileWatcher/emits_truncate_on_touch_when_resend_on_touch_is_enabled (0.10s)
--- PASS: TestFileWatcher/detects_a_file_remove (0.10s)
--- PASS: TestFileWatcher/propagates_a_fingerprints_for_a_new_file (0.00s)
--- PASS: TestFileWatcher/does_not_emit_events_if_a_file_is_touched_and_resend_on_touch_is_disabled (1.00s)
--- PASS: TestFileWatcher/does_not_emit_events_for_empty_files (0.05s)
--- PASS: TestFileWatcher/does_not_emit_events_for_empty_files/issues_a_debug_message_in_logs (0.01s)
--- PASS: TestFileWatcher/does_not_emit_events_for_empty_files/emits_a_create_event_once_something_is_written_to_the_empty_file (0.04s)
--- PASS: TestFileWatcher/does_not_emit_an_event_for_a_fingerprint_collision (0.10s)
--- PASS: TestFileWatcher/does_not_log_warnings_on_duplicate_globs_and_filters_out_duplicates (0.00s)
=== RUN TestFileScanner
=== RUN TestFileScanner/returns_all_files_when_no_limits,_not_including_the_repeated_symlink
=== RUN TestFileScanner/returns_filtered_files,_excluding_symlinks
=== RUN TestFileScanner/returns_files_according_to_excluded_list
=== RUN TestFileScanner/returns_no_symlink_if_the_original_file_is_excluded
=== RUN TestFileScanner/returns_files_according_to_included_list
=== RUN TestFileScanner/returns_no_included_symlink_if_the_original_file_is_not_included
=== RUN TestFileScanner/returns_an_included_symlink_if_the_original_file_is_included
=== RUN TestFileScanner/returns_all_files_except_too_small_to_fingerprint
=== RUN TestFileScanner/returns_all_files_that_match_a_non-standard_fingerprint_window
=== RUN TestFileScanner/does_not_issue_warnings_when_file_is_too_small
=== RUN TestFileScanner/returns_error_when_creating_scanner_with_a_fingerprint_too_small
--- PASS: TestFileScanner (0.00s)
--- PASS: TestFileScanner/returns_all_files_when_no_limits,_not_including_the_repeated_symlink (0.00s)
--- PASS: TestFileScanner/returns_filtered_files,_excluding_symlinks (0.00s)
--- PASS: TestFileScanner/returns_files_according_to_excluded_list (0.00s)
--- PASS: TestFileScanner/returns_no_symlink_if_the_original_file_is_excluded (0.00s)
--- PASS: TestFileScanner/returns_files_according_to_included_list (0.00s)
--- PASS: TestFileScanner/returns_no_included_symlink_if_the_original_file_is_not_included (0.00s)
--- PASS: TestFileScanner/returns_an_included_symlink_if_the_original_file_is_included (0.00s)
--- PASS: TestFileScanner/returns_all_files_except_too_small_to_fingerprint (0.00s)
--- PASS: TestFileScanner/returns_all_files_that_match_a_non-standard_fingerprint_window (0.00s)
--- PASS: TestFileScanner/does_not_issue_warnings_when_file_is_too_small (0.00s)
--- PASS: TestFileScanner/returns_error_when_creating_scanner_with_a_fingerprint_too_small (0.00s)
=== RUN TestFileIdentifier
=== RUN TestFileIdentifier/native_file_identifier
=== RUN TestFileIdentifier/native_file_identifier_with_suffix
=== RUN TestFileIdentifier/path_identifier
=== RUN TestFileIdentifier/fingerprint_identifier
--- PASS: TestFileIdentifier (0.00s)
--- PASS: TestFileIdentifier/native_file_identifier (0.00s)
--- PASS: TestFileIdentifier/native_file_identifier_with_suffix (0.00s)
--- PASS: TestFileIdentifier/path_identifier (0.00s)
--- PASS: TestFileIdentifier/fingerprint_identifier (0.00s)
=== RUN TestTakeOverTags
=== RUN TestTakeOverTags/test-take_over-true
=== RUN TestTakeOverTags/test-take_over-false
--- PASS: TestTakeOverTags (0.00s)
--- PASS: TestTakeOverTags/test-take_over-true (0.00s)
--- PASS: TestTakeOverTags/test-take_over-false (0.00s)
=== RUN TestCreateProspector
=== RUN TestCreateProspector/SetIgnoreInactiveSince
=== RUN TestCreateProspector/SetIgnoreInactiveSince/ignore_inactive_since_set_to_since_last_start
=== RUN TestCreateProspector/SetIgnoreInactiveSince/ignore_inactive_since_set_to_since_first_start
=== RUN TestCreateProspector/SetIgnoreInactiveSince/ignore_inactive_since_not_set
=== RUN TestCreateProspector/file_watcher_and_file_identity_compatibility
=== RUN TestCreateProspector/file_watcher_and_file_identity_compatibility/returns_no_error_for_a_fully_default_config
=== RUN TestCreateProspector/file_watcher_and_file_identity_compatibility/returns_no_error_when_fingerprint_and_identity_is_configured
=== RUN TestCreateProspector/file_watcher_and_file_identity_compatibility/returns_no_error_when_fingerprint_and_other_identity_is_configured
=== RUN TestCreateProspector/file_watcher_and_file_identity_compatibility/returns_error_when_fingerprint_is_disabled_but_fingerprint_identity_is_configured
--- PASS: TestCreateProspector (0.00s)
--- PASS: TestCreateProspector/SetIgnoreInactiveSince (0.00s)
--- PASS: TestCreateProspector/SetIgnoreInactiveSince/ignore_inactive_since_set_to_since_last_start (0.00s)
--- PASS: TestCreateProspector/SetIgnoreInactiveSince/ignore_inactive_since_set_to_since_first_start (0.00s)
--- PASS: TestCreateProspector/SetIgnoreInactiveSince/ignore_inactive_since_not_set (0.00s)
--- PASS: TestCreateProspector/file_watcher_and_file_identity_compatibility (0.00s)
--- PASS: TestCreateProspector/file_watcher_and_file_identity_compatibility/returns_no_error_for_a_fully_default_config (0.00s)
--- PASS: TestCreateProspector/file_watcher_and_file_identity_compatibility/returns_no_error_when_fingerprint_and_identity_is_configured (0.00s)
--- PASS: TestCreateProspector/file_watcher_and_file_identity_compatibility/returns_no_error_when_fingerprint_and_other_identity_is_configured (0.00s)
--- PASS: TestCreateProspector/file_watcher_and_file_identity_compatibility/returns_error_when_fingerprint_is_disabled_but_fingerprint_identity_is_configured (0.00s)
=== RUN TestProspector_InitCleanIfRemoved
=== RUN TestProspector_InitCleanIfRemoved/prospector_init_with_clean_removed_enabled_with_no_entries
=== RUN TestProspector_InitCleanIfRemoved/prospector_init_with_clean_removed_disabled_with_entries
=== RUN TestProspector_InitCleanIfRemoved/prospector_init_with_clean_removed_enabled_with_entries
--- PASS: TestProspector_InitCleanIfRemoved (0.00s)
--- PASS: TestProspector_InitCleanIfRemoved/prospector_init_with_clean_removed_enabled_with_no_entries (0.00s)
--- PASS: TestProspector_InitCleanIfRemoved/prospector_init_with_clean_removed_disabled_with_entries (0.00s)
--- PASS: TestProspector_InitCleanIfRemoved/prospector_init_with_clean_removed_enabled_with_entries (0.00s)
=== RUN TestProspector_InitUpdateIdentifiers
=== RUN TestProspector_InitUpdateIdentifiers/prospector_init_does_not_update_keys_if_there_are_no_entries
=== RUN TestProspector_InitUpdateIdentifiers/prospector_init_does_not_update_keys_of_not_existing_files
=== RUN TestProspector_InitUpdateIdentifiers/prospector_init_does_not_update_keys_if_new_file_identity_is_not_fingerprint
--- PASS: TestProspector_InitUpdateIdentifiers (0.00s)
--- PASS: TestProspector_InitUpdateIdentifiers/prospector_init_does_not_update_keys_if_there_are_no_entries (0.00s)
--- PASS: TestProspector_InitUpdateIdentifiers/prospector_init_does_not_update_keys_of_not_existing_files (0.00s)
--- PASS: TestProspector_InitUpdateIdentifiers/prospector_init_does_not_update_keys_if_new_file_identity_is_not_fingerprint (0.00s)
=== RUN TestMigrateRegistryToFingerprint
=== RUN TestMigrateRegistryToFingerprint/fingerprint_to_native_fails
=== RUN TestMigrateRegistryToFingerprint/path_to_native_fails
=== RUN TestMigrateRegistryToFingerprint/inode_to_fingerprint_succeeds
=== RUN TestMigrateRegistryToFingerprint/path_to_fingerprint_succeeds
=== RUN TestMigrateRegistryToFingerprint/fingerprint_to_fingerprint_fails
--- PASS: TestMigrateRegistryToFingerprint (0.00s)
--- PASS: TestMigrateRegistryToFingerprint/fingerprint_to_native_fails (0.00s)
--- PASS: TestMigrateRegistryToFingerprint/path_to_native_fails (0.00s)
--- PASS: TestMigrateRegistryToFingerprint/inode_to_fingerprint_succeeds (0.00s)
--- PASS: TestMigrateRegistryToFingerprint/path_to_fingerprint_succeeds (0.00s)
--- PASS: TestMigrateRegistryToFingerprint/fingerprint_to_fingerprint_fails (0.00s)
=== RUN TestProspectorNewAndUpdatedFiles
=== RUN TestProspectorNewAndUpdatedFiles/two_new_files
=== RUN TestProspectorNewAndUpdatedFiles/one_updated_file
=== RUN TestProspectorNewAndUpdatedFiles/one_updated_then_truncated_file
=== RUN TestProspectorNewAndUpdatedFiles/old_files_with_ignore_older_configured
=== RUN TestProspectorNewAndUpdatedFiles/newer_files_with_ignore_older
--- PASS: TestProspectorNewAndUpdatedFiles (0.00s)
--- PASS: TestProspectorNewAndUpdatedFiles/two_new_files (0.00s)
--- PASS: TestProspectorNewAndUpdatedFiles/one_updated_file (0.00s)
--- PASS: TestProspectorNewAndUpdatedFiles/one_updated_then_truncated_file (0.00s)
--- PASS: TestProspectorNewAndUpdatedFiles/old_files_with_ignore_older_configured (0.00s)
--- PASS: TestProspectorNewAndUpdatedFiles/newer_files_with_ignore_older (0.00s)
=== RUN TestProspectorHarvesterUpdateIgnoredFiles
--- PASS: TestProspectorHarvesterUpdateIgnoredFiles (0.02s)
=== RUN TestProspectorDeletedFile
=== RUN TestProspectorDeletedFile/one_deleted_file_without_clean_removed
=== RUN TestProspectorDeletedFile/one_deleted_file_with_clean_removed
--- PASS: TestProspectorDeletedFile (0.00s)
--- PASS: TestProspectorDeletedFile/one_deleted_file_without_clean_removed (0.00s)
--- PASS: TestProspectorDeletedFile/one_deleted_file_with_clean_removed (0.00s)
=== RUN TestProspectorRenamedFile
=== RUN TestProspectorRenamedFile/one_renamed_file_without_rename_tracker
=== RUN TestProspectorRenamedFile/one_renamed_file_with_rename_tracker
=== RUN TestProspectorRenamedFile/one_renamed_file_with_rename_tracker_with_close_renamed
--- PASS: TestProspectorRenamedFile (0.00s)
--- PASS: TestProspectorRenamedFile/one_renamed_file_without_rename_tracker (0.00s)
--- PASS: TestProspectorRenamedFile/one_renamed_file_with_rename_tracker (0.00s)
--- PASS: TestProspectorRenamedFile/one_renamed_file_with_rename_tracker_with_close_renamed (0.00s)
=== RUN TestOnRenameFileIdentity
=== RUN TestOnRenameFileIdentity/identifier_name_from_meta_is_kept
=== RUN TestOnRenameFileIdentity/identifier_from_prospector_is_used
--- PASS: TestOnRenameFileIdentity (0.00s)
--- PASS: TestOnRenameFileIdentity/identifier_name_from_meta_is_kept (0.00s)
--- PASS: TestOnRenameFileIdentity/identifier_from_prospector_is_used (0.00s)
PASS
ok github.com/elastic/beats/v7/filebeat/input/filestream 6.756s
```

However the same thing ran on `main` outputs `837 119` lines, that's 125Mb.
```
git checkout main
go test -v -count=1
```

This output is just too large to be of any use and it is impossible to see which tests were run.

Another problem of the new behaviour is printing the stack trace at error level by default, this makes the output look like a panic, which can be very confusing.

# Proposal
Revert to the previous behaviour (like from `v0.18.9`) of not having development/test loggers logging to stdout/err and do not print the stack trace at level error.