Remove unnecessary cache definition in rake karma test

Closes #32119


Former-commit-id: 77f2ec4f

.gitlab-ci.yml

@@ -408,9 +408,6 @@ rake gitlab:assets:compile:
     - webpack-report/
 rake karma:
-  cache:
-    paths:
-      - vendor/ruby
   stage: test
   <<: *use-pg
   <<: *dedicated-runner