Remove tooltip from MR actions dropdown

What does this MR do and why?

• Removes tooltip from Merge request actions dropdown, in favor of the title and aria-label attributes
• Why? It occasionally appears on the bottom (necessary when there's no room at the top), covering the Notifications toggle.
  • You can't click the toggle unless you click away

Screenshots or screen recordings

Before	After

How to set up and validate locally

(not reproducible all the time)

• Hover over and click the ellipsis menu (Merge request actions) in the top right corner of the MR

#394879 (closed)