Revert "fix(CI): #2441 disable test_front because most tests have become stale"

This reverts commit edc7f9d872.

.gitlab-ci.yml

@@ -500,11 +500,8 @@ docker:
       artifacts: true
     - job: test_api
       optional: true
-    # The test_front job is currently disabled
-    # TODO: Discuss if we need tests, and what kind of tests would be useful for the front:
-    # https://dev.funkwhale.audio/funkwhale/funkwhale/-/issues/2345
-    # - job: test_front
-    #   optional: true
+    - job: test_front
+      optional: true
   rules:
     - if: $CI_COMMIT_TAG
       variables: