bext: refactor integration tests

Created by: taras-yemets

Closes https://github.com/sourcegraph/sourcegraph/issues/33484

1. Changes browser extension integration tests snapshots compression mechanism. We used git lfs to store snapshots before, but used too much bandwidth to fetch them. This PR suggests compressing the snapshots after recording and adding compressed files to repo index. Snapshots are decompressed before and removed after running integration tests.
2. Enables browser extension integration tests in the pipeline as we no longer fetch snapshots with git-lfs.
3. Removes browser extension after install page integration test as neither Polly nor Percy support non http(s) protocols.
4. Refactors GitHub search results pages integration tests to omit 429 HTTP errors causing recordings to fail. There's still no guarantee we won't have this error while recording all integration tests at once in the future.

Test plan

• run sg test bext-build
• run yarn workspace @sourcegraph/browser record-integration and ensure that
  • it passes
  • there are no test recording files (.har) in git index
  • compressed recordings (.har.gz) are tracked by git
• run sg test bext-integration and ensure that
  • tests pass
  • there are no test recording files (.har) in git index

App preview:

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