Remove workaround for pywb's wombat.js bug

[acelaya]

This PR reverts the changes introduced in #6119 and #6227, which were meant to work around webrecorder/wombat#133

That bug was fixed in webrecorder/wombat#134 and is now part of latest pywb, and already part of viahtml after merging hypothesis/viahtml#657.

Testing steps

1. Check out this branch
2. Open viahtml locally, and run python ./bin/build_static.py. This will copy and expose pywb static assets, including wombat.js
3. Go to http://localhost:9083/https://www.example.com/ and open the "Version" tab of the help panel.
   
4. Click "Copy version details". You should see a success toast message.

Note

We are not using GitHub revert functionality, because changes were applied in two different PRs, and that would require doing the revert in two steps.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.43%. Comparing base (65cc9b6) to head (360c8dc).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6356      +/-   ##
==========================================
- Coverage   99.43%   99.43%   -0.01%     
==========================================
  Files         271      271              
  Lines       10239    10238       -1     
  Branches     2425     2425              
==========================================
- Hits        10181    10180       -1     
  Misses         58       58              

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[robertknight]

I haven't done a manual test of this myself, but the change looks fine.