[native][lib] Gate encrypted media uploads on Comm staff community

Summary: We're initially launching this to the Comm staff community so we can test things out.

Test Plan:
I loaded up my local dev environment, which has a mirrored copy of the Comm community.

1. I uploaded an encrypted photo to the Comm community root from native and confirmed it appeared as encrypted in the MySQL database (has an encryptionKey)
2. I uploaded an encrypted photo to the Comm dev team channel from native and confirmed it appeared as encrypted in the MySQL database (has an encryptionKey)
3. I confirmed I was able to view the encrypted media from the web
4. I confirmed I was able to view the encrypted media from native, but only after the initial upload
5. I confirmed that after logging out and back in on native, the encrypted media upload appears as a messageTypes.UNSUPPORTED ("ashoat sent a photo")
6. I uploaded a photo to a different chat and confirmed it was NOT encrypted
7. I uploaded a photo to the Comm dev team channel from the web and confirmed it was NOT encrypted
8. I sent a message with a photo and a video to the Comm community root from native and confirmed it resulted in three encrypted uploads in the MySQL database (all had an encryptionKey, one was for the thumbnail) and that the video was viewable from the web

Reviewers: atul, bartek

Reviewed By: atul

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D7335