[web] Gate encrypted media uploads on Comm staff community

Summary:
Similiar to D7335 but for web.

Most of the component code passes threadID only so I had to add a separate selector for threadInfo.

Test Plan:

• In my local environment, created a community with ID from lib/facts/commStaffCommunity using the create-community script.
• Sent a photo to that community
• Sent the same photo to a chat in GENESIS community
• Ensured that the uploads table has two new entries: one containing encryptionKey and the other one doesn't. (also looked at the thread column)
• Created subchats and threads in both communities, repeated.

Reviewers: ashoat, atul

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D7434