[in-app-menu] add toggle menu icon

[Araxeus]

• Adds an icon that allows hiding/unhiding the menu by clicking it

  

• Fix hide menu not working with in-app-menu enabled – by bumping custom-electron-titlebar following fix updateMenu(null) not working AlexTorresDev/custom-electron-titlebar#204

• Change the keybind to ` (backtick) because Esc is problematic since youtube already uses it
  And also make it always active (not only when hide-menu is enabled – since it's only a shortcut for clicking the icon)

  Might have to ignore the event if the searchbox is open like [PiP] fix hotkey activating when typing in the search box #1025 - should probably refactor the added key listener so that it can be used here too

Outdated Notes

This can only be merged after #987 is resolved
meanwhile for testing you need to replace youtube-music\node_modules\custom-electron-titlebar\dist\index.js with an updated version, you have 2 options for that:

• Download the one I built on my pc: index.zip
• Build it yourself: based on the branch from fix updateMenu(null) not working AlexTorresDev/custom-electron-titlebar#204