Fix: IVF writer writing invalid timestamp value into frame headers

[radekg]

Description

This PR fixes the incorrect header timestamp written into the frame headers.

Reference issue

Fixes #2384

[edaniels]

Thanks @radekg!

[edaniels]

LGTM, ty for the fix and added test

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 65.08%. Comparing base (8ec98b7) to head (9202b3c).

Files	Patch %	Lines
pkg/media/ivfwriter/ivfwriter.go	50.00%	0 Missing and 2 partials ⚠️

❗ There is a different number of reports uploaded between BASE (8ec98b7) and HEAD (9202b3c). Click for more details.

HEAD has 2 uploads less than BASE

Flag	BASE (8ec98b7)	HEAD (9202b3c)
go	2	0

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #2853       +/-   ##
===========================================
- Coverage   78.94%   65.08%   -13.87%     
===========================================
  Files          89       67       -22     
  Lines        8335     3239     -5096     
===========================================
- Hits         6580     2108     -4472     
+ Misses       1278     1005      -273     
+ Partials      477      126      -351     

Flag	Coverage Δ
go	?
wasm	65.08% <50.00%> (ø)

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[edaniels]

@radekg can you fix up the error from the meta lint (commit message length)?