Fix Illegible text in audio bus editor

[SirQuartz]

This pull request fixes an issue with the audio bus editor where the text would be illegible regardless of the theme being used.

Resolves: #50583

[YuriSizov]

I'm not sure why you would need to change anything in the default theme. You just need to change the related color in the editor theme based on the dark theme flag. If there is no color constant specific to the bus name for some reason, it needs to be defined.

This also isn't the greatest color in general, midtones are still not very readable, on either theme preset. And the empty line is unnecessary.

[YuriSizov]

@SirQuartz That just means that there are definitions in the editor theme missing. Those definitions are only created in the editor_themes.cpp file. The default_theme.cpp files should not be touched to fix an issue with the editor theme, because it does not contain the editor theme. It contains the default engine theme, the one you see in the projects, not in the editor.

If you think that every LineEdit in the editor, provided they are set to not be editable, is affected by this you need to create or adjust definitions for font_uneditable_color in the editor theme definitions. Somewhere around here:

https://github.com/godotengine/godot/blob/e3a86d54c3be39982384a5e89c151ecfefc62b00/editor/editor_themes.cpp#L1022-L1032

There is likely already a good color available that respects the color scheme that you can use here.

Alternatively we can consider swapping the LineEdit for a Label when it's not editable and using some other color.

[SirQuartz]

@pycbouh Ok, I've fixed everything, and this should be a much cleaner implementation.

[akien-mga]

Thanks!

[akien-mga]

It seems like font_uneditable_color doesn't exist in 3.x so a different fix would be needed there.

[SirQuartz]

It seems like font_uneditable_color doesn't exist in 3.x so a different fix would be needed there.

I see, I'll look into a solution for 3.x as well.

[SirQuartz]

Thanks!

@akien-mga See: #50646