This diff introduces the barebones navigational logic needed for introducing `TagFarcasterChannelNavigator` and the `TagFarcasterChannel` screen. Subsquent diffs will handle extending both of these to match the UI/UX with the rest of the app
Linear tasks: https://linear.app/comm/issue/ENG-7538/introduce-tag-farcaster-channel-option-in-the-community-actions-menu + https://linear.app/comm/issue/ENG-7539/introduce-tagfarcasterchannelmodal-screen + https://linear.app/comm/issue/ENG-7540/introduce-navigational-logic-for-tagfarcasterchannelmodal