R1:7f5919de1c1c

Don't load attached files for profile images

Summary:
Ref T8478. I think the cycle is:

- Conpherence Thread > Loads handle for participant > loads file for profile image > loads attached files to check visibility > loads conpherence thread > ...

So, specifically, someone attached their profile image to a thread or message somewhere.

This breaks the cycle by stopping the attached-files visibility check from happening, since we don't need it. This seemed like the easiest link in the chain to break.