fix transient dropdown test failures
fix some flaky dropdown tests
- change click target to button instead of wrapper element
fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/37052 fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/34436
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
fix some flaky dropdown tests
fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/37052 fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/34436