Fix flaky ingest reports service spec
What does this MR do and why?
Some of the tests in ee/spec/services/security/ingestion/ingest_reports_service_spec.rb
file are flaky.
This can be reproduced by running the specs in this file with seed 27931
;
bundle exec rspec ee/spec/services/security/ingestion/ingest_reports_service_spec.rb --seed 27931