Fix built-in script live reloading

[KoBeWi]

When saving a built-in script while the game is running, it may trigger errors. The reasons are twofold:

• The debugger tries to reload all received paths, even scripts that aren't loaded. I don't know what's the purpose, but it does not work for built in scripts, as their scene has to be loaded for them to be recognized.
• The editor was sending unnecessary script paths. When you save a scene, all currently open built-in scripts would be live reloaded.

Fixes #105891

[kitbdev]

• Tested, fixes #105891

[Repiteo]

Thanks!