fix: Set native menus per-window

[Stedoss]

Previously when a new window was created Menu.setApplicationMenu() was called, which would change all windows' native menu to the newly created one - causing every window menu to reference the newly created BrowserWindow. This causes weird behaviour with old windows (see Before video).

Now each window is set their own Menu instance which will have their own BrowserWindow.

Note

This mostly impacts Windows and Linux, may need some testing on Mac to make sure behaviour is still as expected.

Before

electron_yApfFkBxZg.mp4

After

iPiHNTZGTX.mp4

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