debt - let menu listen to (new) menu registry change events instead of listing to the extension host being ready. that simplifies this a lot and help with show menu sooner

#53526

This reverts commit cd1a6b4f.

Fixes #61642

Remove logic added by ab77235b. The original concern was that we would end up showing the light bulb too often but its not sure this will be a problem in practice.

Fixes #62072