wrong count when batch altering tasks

#### To report a bug...

* What command(s) did you run?

task test delete

* What did you expect to happen?

correct count of tasks that would be altered

* What actually happened?

"This command will alter 70 tasks"

but in fact only

"Deleted 4 tasks."

others:

Task 3ce8893c 'test server' is not deletable.
Task 3bad08e4 'test server 2' is not deletable.
Task 767b9e97 'test fra UI 2' is not deletable.
...

* Paste the output of the ```task diag``` command.

task 2.6.1
Platform: Darwin

Compiler
Version: Apple LLVM 13.0.0 (clang-1300.0.29.3)
Caps: +stdc +stdc_hosted +LP64 +c8 +i32 +l64 +vp64 +time_t64
Compliance: C++17

Build Features
CMake: 3.21.3
libuuid: libuuid + uuid_unparse_lower
libgnutls: 3.6.16
Build type: Release

Configuration
File: /Users/kiil/.taskrc (found), 2707 bytes, mode 100644
Data: /Users/kiil/GD/MIS/.task (found), dir, mode 40755
Locking: Enabled
GC: Enabled
rc.editor: nvim

Hooks
System: Enabled
Location: /Users/lennartkiil/GD/MIS/.task/hooks
Active: on-modify.timewarrior (executable)
Inactive:

Tests
Terminal: 230x63
Dups: Scanned 597 tasks for duplicate UUIDs:
No duplicates found