muxer: remove timestamp normalization

[aler9]

No description provided.

[codecov]

Codecov Report

Merging #85 (fef4972) into main (ea7305d) will decrease coverage by 0.03%.
The diff coverage is 88.00%.

@@            Coverage Diff             @@
##             main      #85      +/-   ##
==========================================
- Coverage   68.88%   68.85%   -0.03%     
==========================================
  Files          42       42              
  Lines        3689     3651      -38     
==========================================
- Hits         2541     2514      -27     
+ Misses        965      955      -10     
+ Partials      183      182       -1     

Files Changed	Coverage Δ
muxer_server.go	70.55% <ø> (-0.21%)	⬇️
muxer_segmenter_mpegts.go	78.04% <76.19%> (-2.07%)	⬇️
muxer_segment_fmp4.go	72.17% <93.33%> (ø)
muxer_part.go	95.38% <100.00%> (ø)
muxer_segmenter_fmp4.go	69.59% <100.00%> (+1.62%)	⬆️

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