Follow-up from "Hide its tooltip when merge request menu is shown"

The following discussion from !116923 (merged) should be addressed:

• @thutterer started a discussion: (+8 comments)

  Quickfix MR ... because it drove me nuts 😬

  @gitlab-org/manage/foundations/engineering

  • Is there a better way to hide that tooltip?
  • How would I best test this? Volunteers, feel free to push to this branch!
  • Should we do the same fot the "Create new..." menu tooltip?

In other words:

• Do the same for the Create new... menu tooltip
• (optional) Figure out how to test this tooltip behaviour
• (optional) Figure out how to "upstream" this sort of fix to GlTooltip