fix(tests): Fixes for old Safari

[mister-ben]

Description

Followup to #8356. The issue with older Safari with document.styleSheets is a little different than thought. The problem is that Safari doesn't necessarily return rules verbatim, so a text comparison wasn't working. A rule with a shorthand property like background: white; is returned as background-color: white;.

Specific Changes proposed

Changes the test to use a rule that won't be changed.
Revert skipping the test on Safari from #8356 as we can make that test work after all.
Change copyStyleSheets to use styleSheet.media.mediaText when setting media. On old Safari this has to be a string, other browsers allow the MediaList object to be set.

Test ran on browserstack passed here:
https://github.com/mister-ben/video.js/actions/runs/5600546784/jobs/10243092934

[codecov]

Codecov Report

Merging #8368 (feee88d) into main (452a918) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #8368   +/-   ##
=======================================
  Coverage   82.71%   82.71%           
=======================================
  Files         113      113           
  Lines        7578     7578           
  Branches     1821     1821           
=======================================
  Hits         6268     6268           
  Misses       1310     1310           

Impacted Files	Coverage Δ
src/js/utils/dom.js	66.41% <100.00%> (ø)

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[wseymour15]

+1, good comment describing the issue with Safari!

[misteroneill]

Nice, was just looking at these test failures.