Throw error when p_start_time is negative when starting an audio playback stream

[garrettgu10]

Fixes #89390.

I'm not sure if this is idiomatic/desired behavior, feel free to correct me :-)

[Malcolmnixon]

All existing streams silently clamp any positions greater than the stream end/length; however they are not consistent as to how they handle positions less than the stream start (e.g. negative positions):

Type	Results
MP3	Negative start or seek positions are passed to AudioStreamPlaybackMP3::seek which fails to clamp negative values resulting in extremely large positive values being passed to the minimp3 mp3dec_ex_seek function.
Ogg Vorbis	Negative start or seek positions are passed to AudioStreamPlaybackOggVorbis::seek which fails to clamp negative values resulting in large positive frame values.
WAV	Negative start or seek positions are passed to AudioStreamPlaybackWAV::seek which clamps them to 0.

If clamping occurs at the end, I feel it would be more consistent to apply silent clamping at the start as well. This may be beneficial for code performing relative seeking in a stream.

[akien-mga]

@Malcolmnixon Clamping negative start/seek positions consistently as you suggest seems good to me. Would you like to make an alternative PR with that approach?