Resolve "Add "Submit feedback" in-product feedback link"

What does this MR do?

This MR adds a link to the help menu which will direct users to submit feedback.

What are the relevant issue numbers?

• Closes #43623 (closed)
• Requires gitlab-com/www-gitlab-com!12383 (merged) to be merged

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Conforms to the code review guidelines
• Conforms to the style guides