[lib] Rename sansFarcaster variable names and types to Traditional*

Summary:
Including farcaster in all of these types and variables when it's often completely irrelevant doesn't make sense. Calling them Legacy* doesn't quite make sense either since they're def not being phased out, so settled on Traditional* to keep consistent with D11602

Depends on D11602

Test Plan: NA, simple rename

Reviewers: ginsu, tomek, will, varun

Reviewed By: ginsu

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D11603