[lib] fix useFCNames

Summary: resolves https://linear.app/comm/issue/ENG-9337/fix-broken-usefcnames

Test Plan:
https://gist.github.com/vdhanan/9b6a003fb731f7e23fac54e8d594fdef

with patch, i was able to see my farcaster username logged

Reviewers: ashoat, will

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D13387