[ENGG-1696] MV3: support for rq_request_initiator_origin() predefined function

[nafees87n]

Closes issue:

📜 Summary of changes:

✅ Checklist:

• Make sure linting and unit tests pass.
• No install/build warnings introduced.
• Verified UI in browser.
• For UI changes, added/updated analytics events (if applicable).
• For changes in extension's code, manually tested in Chrome and Firefox.
• For changes in extension's code, both MV2 and MV3 are covered.
• Added/updated unit tests for this change.
• Raised pull request to update corresponding documentation (if already exists).

🧪 Test instructions:

🔗 Other references:

[deepsource-io]

Here's the code health analysis summary for commits 15da788..b022b98. View details on DeepSource ↗.

Analysis Summary

Analyzer	Status	Summary	Link
Shell	✅ Success		View Check ↗
JavaScript	❌ Failure	❗ 2 occurences introduced 🎯 1 occurence resolved	View Check ↗

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