[native] add unlinkFarcasterAccount to CommRustModule

Summary:
C++ code (including codegen code) to make the rust client method from previous diff callable from JS

Depends on D11430

Test Plan: tested in next diff by calling the unlink method from JS

Reviewers: bartek

Reviewed By: bartek

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D11431