9ee3fb813f
## Description This PR changes the `MenuAnchor` implementation in order to always show the menu on the root overlay. Doing so menus can't be hidden by other widgets especially when using go_router. See [[go_router] DropdownMenu behind NavigationBar](https://github.com/flutter/flutter/issues/155034) where the DropdownMenu menu was displayed behind the navigation bar. I did not make this configurable for the moment to avoid introducing a new parameter until there is a clear use case for it. ## Related Issue Fixes [[go_router] DropdownMenu behind NavigationBar](https://github.com/flutter/flutter/issues/155034). ## Tests Adds 1 test.