broadcaster: Fix video compatibility check

[j0sh]

What does this pull request do? Explain your changes. (required)

Fixes video compatibility check that led to excessive transcoder re-initialization.

Not all fields will be identical segment-to-segment, particularly DurationSecs.
This caused unnecessary transcoder re-initialization.

Specific updates (required)

• Add a videoCompatible helper to check for video compatibility
• Add unit tests for the videoCompatible helper

How did you test each of these updates (required)

1. Unit tests for the helper
2. Manual testing to ensure transcoding session gets reused

Does this pull request close any open issues?

Checklist:

• Read the contribution guide
• make runs successfully
• All tests in ./test.sh pass
• README and other documentation updated
• Pending changelog updated

[leszko]

Good finding @j0sh 🏅

[j0sh]

Added a check for the audio codec too, just to be safe - 6016b9b

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 57.36772%. Comparing base (48a92a1) to head (c046e6f).
Report is 1 commits behind head on master.

Additional details and impacted files

@@                 Coverage Diff                 @@
##              master       #3164         +/-   ##
===================================================
+ Coverage   57.35155%   57.36772%   +0.01617%     
===================================================
  Files             92          92                 
  Lines          15813       15819          +6     
===================================================
+ Hits            9069        9075          +6     
  Misses          6139        6139                 
  Partials         605         605                 

Files with missing lines	Coverage Δ
server/mediaserver.go	67.71429% <100.00000%> (+0.18555%)	⬆️

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Files with missing lines	Coverage Δ
server/mediaserver.go	67.71429% <100.00000%> (+0.18555%)	⬆️