Fix errors when creating bezier component tracks.

[SaracenOne]

• Closes Bezier curves affecting sub-components of property will produce a 'Could not determine track hint' warning. #96788
• Closes "Index p_track = 0 is out of bounds (tracks.size() = 0)" Error on new bezier track creation in AnimationPlayer #96849

[ImpishOaths]

Darn, I think one of those bugs was my fault. Didn't realize track_find_key would throw an error if the track_id is out of bounds. Thanks for fixing it!

[fire]

@TokageItLab may want a look

[akien-mga]

Thanks!