Merge branch 'bugfix_coverage_fuzzing_merge_event' into 'master'

Bugfix: remote double trigger on merge_request event for coverage fuzzing

See merge request gitlab-org/gitlab!41906

changelogs/unreleased/bugfix_coverage_fuzzing_merge_event.yml

+---
+title: Prevent merge requests from triggering coverage fuzzing jobs
+merge_request: 41906
+author:
+type: fixed

lib/gitlab/ci/templates/Security/Coverage-Fuzzing.gitlab-ci.yml

@@ -34,5 +34,5 @@ variables:
   rules:
     - if: $COVFUZZ_DISABLED
       when: never
-    - if: $GITLAB_FEATURES =~ /\bcoverage_fuzzing\b/
+    - if: $CI_COMMIT_BRANCH && $GITLAB_FEATURES =~ /\bcoverage_fuzzing\b/
     - if: $CI_RUNNER_EXECUTABLE_ARCH == "linux"