rubyTests failing in 8.12.2 logstash

Repro line:

./gradlew rubyTests --stacktrace

Below errors are seen during execution of above command:
org.logstash.RSpecTests > rspecTests[core tests] FAILED java.lang.AssertionError: RSpec test suite core testssaw at least one failure. at org.junit.Assert.fail(Assert.java:88) at org.logstash.RSpecTests.rspecTests(RSpecTests.java:72

Below are some of the failures:

rspec ./logstash-core/spec/logstash/api/modules/root_spec.rb:26 # LogStash::Api::Modules::Root should respond to root resource rspec ./logstash-core/spec/logstash/api/modules/root_spec.rb:23 # LogStash::Api::Modules::Root should return a 404 to unknown request rspec './logstash-core/spec/logstash/api/modules/node_stats_spec.rb[1:1]' # LogStash::Api::Modules::NodeStats should return a 404 to unknown request rspec './logstash-core/spec/logstash/api/modules/node_stats_spec.rb[1:2:1]' # LogStash::Api::Modules::NodeStats GET / should respond OK rspec './logstash-core/spec/logstash/api/modules/node_stats_spec.rb[1:2:3]' # LogStash::Api::Modules::NodeStats GET / should set 'jvm.uptime_in_millis' at '/' to be a 'Numeric' rspec './logstash-core/spec/logstash/api/modules/node_stats_spec.rb[1:2:4]' # LogStash::Api::Modules::NodeStats GET / should set 'jvm.threads.count' at '/' to be a 'Numeric' rspec './logstash-core/spec/logstash/api/modules/node_stats_spec.rb[1:2:5]' # LogStash::Api::Modules::NodeStats GET / should set 'jvm.threads.peak_count' at '/' to be a 'Numeric' rspec './logstash-core/spec/logstash/api/modules/node_stats_spec.rb[1:2:6]' # LogStash::Api::Modules::NodeStats GET / should set 'jvm.gc.collectors.young.collection_count' at '/' to be a 'Numeric' rspec './logstash-core/spec/logstash/api/modules/node_stats_spec.rb[1:2:7]' # LogStash::Api::Modules::NodeStats GET / should set 'jvm.gc.collectors.young.collection_time_in_millis' at '/' to be a 'Numeric' rspec './logstash-core/spec/logstash/api/modules/node_stats_spec.rb[1:2:8]' # LogStash::Api::Modules::NodeStats GET / should set 'jvm.gc.collectors.old.collection_count' at '/' to be a 'Numeric'

Most of the failures are like below, with Argument Errors as:

` LogStash::Api::Modules::Logging#logging when setting a logger's log level should throw error when key logger is invalid
Failure/Error: status = RSpec::Core::Runner.run(ARGV.empty? ? ($JUNIT_ARGV || ["spec"]) : ARGV).to_i

       ArgumentError:
         Setting "xpack.geoip.downloader.enabled" doesn't exist. Please check if you haven't made a typo.
       # ./logstash-core/lib/logstash/settings.rb:104:in `get_setting'
       # ./logstash-core/lib/logstash/settings.rb:136:in `get_value'
       # ./x-pack/lib/geoip_database_management/manager.rb:52:in `initialize'
       # ./logstash-core/lib/logstash/agent.rb:633:in `initialize_geoip_database_metrics'
       # ./logstash-core/lib/logstash/agent.rb:97:in `initialize'
       # ./logstash-core/spec/support/helpers.rb:57:in `make_test_agent'
       # ./logstash-core/spec/support/shared_contexts.rb:62:in `block in <main>'
       # ./lib/bootstrap/rspec.rb:36:in `<main>'

`

Reproduces locally?: yes

Applicable branches: 8.12.0 onwards

Failure history:
Fails from 8.12.0

Run ./gradlew rubyTests --stacktrace and start with logstash-core/lib/logstash/settings.rb:104 and :136, then follow the x-pack/lib/geoip_database_management/manager.rb:52 path through logstash-core/lib/logstash/agent.rb. Compare the failing API specs and helpers against the 8.12.0-onwards setting behavior. Done means the listed RSpec failures no longer occur and rubyTests passes.