Feature/ttml isobmff validation

[mohithshuka]

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{pull request content here}

[mohithshuka]

This PR adds validation for TTML tracks inside ISOBMFF (MP4) containers.

Changes include:

• Detecting and validating TTML samples in ISOBMFF
• Rejecting malformed or unsupported TTML entries
• Improving error handling and logging for invalid TTML streams

Tested with MP4 files containing TTML subtitles.

[cfsmp3]

This shouldn't be a PR. It doesn't even build! PLEASE STOP WITH THIS SPAM OR YOU WILL BE BANNED.