This makes it easier to track which objects are disposable, since we can use findAllReferences on them

These classes do not (and should not) modify the input actions array. Use `ReadonlyArray` to enforce this

#70020

* Revert "Revert "Make menubar its own widget and add overflow (#63954)""

This reverts commit fa87e67e.

* add checks for whencustom menubar is not present

This reverts commit aedd4402.

* working state

* fix keybindings and add compact submenu mode

* fix blur

* fix mnemonics in overflow menu

* fix issues with window resizing

* switch to ellipsis

In these cases, the programmer has explicitly indicated that the type should be nullable

* make actionbar support different trigger keys

* add some undefined checks

We compile using the alwaysStrict flag so these directives are not needed

fixes #56648