dont set video track size

[mjh1]

this was misleading as it is actually the total file size (video and audio) we were not using the field anywhere anyway

[codecov]

Codecov Report

Merging #440 (5fd805e) into main (aa0aa76) will increase coverage by 0.01778%.
The diff coverage is 25.00000%.

@@                 Coverage Diff                 @@
##                main        #440         +/-   ##
===================================================
+ Coverage   55.68327%   55.70105%   +0.01778%     
===================================================
  Files             39          39                 
  Lines           3132        3131          -1     
===================================================
  Hits            1744        1744                 
+ Misses          1243        1242          -1     
  Partials         145         145                 

Impacted Files	Coverage Δ
video/probe.go	0.00000% <0.00000%> (ø)
clients/mediaconvert.go	71.99074% <100.00000%> (ø)

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Impacted Files	Coverage Δ
video/probe.go	0.00000% <0.00000%> (ø)
clients/mediaconvert.go	71.99074% <100.00000%> (ø)