Frame rate is correctly determined using the media duration from the `mdhd` box and the sample count from the `stsz` box. The fallback calculation using the edited sample count and `tkhd` box duration is incorrect, as added silence at the beginning can increase the track duration without affecting the sample count.
No-op change, as we never use the fallback calculation for our sample files in the test.
PiperOrigin-RevId: 743081118
(cherry picked from commit c0e518df9709cc858c0610e4694d8753bdb638b7)
2bdf632369