Add Alt + Right mouse button functionality to all 2D modes in the editor

[Broken1334]

Describe the project you are working on

Any 2D project

Describe the problem or limitation you are having in your project

Currently in 2D Alt+RMB ("Show list of selectable nodes") works only in Select mode.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Add Alt+RMB functionality to all 2D modes, like in 3D. It helps to keep UX consistency and add more flexibility.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

N/A

If this enhancement will not be used often, can it be worked around with a few lines of script?

N/A

Is there a reason why this should be core and not an add-on in the asset library?

N/A

[Arnklit]

Should be resolved by godotengine/godot#99795