assistant: restore upstream behaviour for source control commit attachments

[sharon-wang]

• Addresses Assistant: cannot get commit information when running in Workbench #9181
• Removes the gating that was added in Assistant: turn on git integrations by default #9066, since I'm no longer seeing issues with Add Context... --> "Source Control..." on Workbench

Release Notes

New Features

• N/A

Bug Fixes

• N/A

QA Notes

Add Context... --> "Source Control..." should be available by default on Web/Workbench again

[github-actions]

E2E Tests 🚀
This PR will run tests tagged with: @:critical

^{readme  valid tags}