fix: empty audio track

[xiaoyuhen]

fix: empty audio track

Description

In some case, we have empty edit media time, If we dont ignore the empty edit media time, we will have audio/video sync problem. see #14

How Has This Been Tested?

• this video can play normally
• the example video can play normally

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[codecov-io]

Codecov Report

Merging #52 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master      #52   +/-   ##
=======================================
  Coverage   52.86%   52.86%           
=======================================
  Files         123      123           
  Lines        1678     1678           
=======================================
  Hits          887      887           
  Misses        791      791

Impacted Files	Coverage Δ
packages/griffith-mp4/src/mp4/mp4Probe.js	0% <ø> (ø)	⬆️
packages/griffith-mp4/src/mse/controller.js	0% <ø> (ø)	⬆️
...s/griffith-mp4/src/mp4/utils/getSamplesInterval.js	95.08% <100%> (ø)	⬆️

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