[blob] Don't check if the invite link is reserved
Summary:
We're checking this only on the keyserver side for now.
Test Plan: Run a local blob service, comment out reserved link check on a keyserver. Create a reserved link, open it and verify that the blob was downloaded using the browser inspector. Also check if offensive links check still works on keyserver.
Reviewers: bartek, varun
Reviewed By: bartek
Subscribers: ashoat
Differential Revision: https://phab.comm.dev/D12281