Swapped the locations of scribble_external_sound_exists and scribble_external_sound_remove functions so that they are in the scripts with the same name

[KormexGit]

The function "scribble_external_sound_exists" was in the script "scribble_external_sound_remove", and vice versa. Having them backwards made scribble unable to compile in the latest 2024.2 beta, swapping them fixes that and lets scribble compile. Edit: Just got word that the compile issue in beta will be fixed before release, but leaving this PR since the functions might as well get swapped to the right scripts