Fix failing e2e test: qa/specs/features/browser_ui/3_create/merge_request/create_merge_request_spec.rb

What does this MR do?

On staging new projects now have existing labels, which displays a different layout causing a test to fail because an expected image is not displayed.

There is a similar image shown on the page with existing labels, so this change adds a selector so the test can successfully wait for the image to appear.

What are the relevant issue numbers?

Closes gitlab-org/quality/staging#38 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer