fix: eliminate unnecessary buffer allocations during audio playback

[Danielku15]

Issues

Fixes #2714

Proposed changes

1. Avoid unnecessary Float array allocations during playback in C# and Kotlni
2. Write full buffer to AudioTrack to avoid looping and buffer requests when input buffer is drained.
3. Follow up on 2: update position tracking to account for "silence" in edge cases.

Checklist

• I consent that this change becomes part of alphaTab under it's current or any future open source license
• Changes are implemented
• New tests were added

Further details

• This is a breaking change
• This change will require update of the documentation/website