Mirror the rule with .frontend:rules:compile-test-assets

When set ~"pipeline:run-all-rspec" without having
compile-test-assets-as-if-foss, the pipeline will be invalid for
those as-if-foss jobs.

.gitlab/ci/rules.gitlab-ci.yml

@@ -484,8 +484,8 @@
   rules:
     - <<: *if-not-ee
       when: never
-    - <<: *if-merge-request  # Always run for MRs since `compile-test-assets as-if-foss` is either needed by `rspec foss-impact` or the `rspec * as-if-foss` jobs.
-      changes: *code-backstage-qa-patterns
+    - changes: *code-backstage-qa-patterns
+    - <<: *if-merge-request-title-run-all-rspec
 
 .frontend:rules:default-frontend-jobs:
   rules: