Add cdn videos to report-only CSP media-src

[janbrasna]

One-line summary

Follows up from #15548 adding an older host used for serving videos in the past to add to media-src policy recently added to take precedence over default-src wildcard fallbacks.

Significant changes and points to review

This is a new addition, so instead of allowing all the default hosts we're trying to explicitly define the sources (and/or paths if needed) to have an exhaustive list of known media hosts being used around the site.

Issue / Bugzilla link

#15546

Testing

curl -I http://localhost:8000/de/

[robhudson]

🎥

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.92%. Comparing base (f8d81da) to head (4bf4057).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15550   +/-   ##
=======================================
  Coverage   78.92%   78.92%           
=======================================
  Files         158      158           
  Lines        8279     8279           
=======================================
  Hits         6534     6534           
  Misses       1745     1745           

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