[lib/native] introduce useCreateFarcasterChannelTag

Summary: We are going to want both this logic on both web and native. Created this shared hook that factors out all the shared logic for creating a farcaster channel tag

Test Plan: flow + confirmed no regressions with creating a farcaster channel tag on native

Reviewers: inka, kamil

Reviewed By: inka

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D12535