feat: include full frozen stream stats in FrozenVideoTrackDetector result

[vatson]

Summary

FrozenVideoTrackDetector previously reported only SSRCs of frozen streams in the statsSample.
This PR extends the output to include the full frozen stream objects, which contain additional properties such as:

• avgFreezeDurationMs
• frozenDurationPct

Why

These extra fields are very useful for debugging and monitoring, since they expose the actual measured freeze durations instead of just identifiers.
The change is backwards-compatible because the ssrcs array is still included.

Possible follow-up

If the team prefers more control, I could make this behavior optional by introducing a verbose (or similar) flag in the detector’s constructor. This would allow toggling between minimal and detailed output without changing existing integrations.