Silent failure when registering an fname

[spengrah]

In /farcaster-#, I thought I had (after a workaround, see #262) successfully registered an fname. However, that fid still displayed as "New Account" in /settings, even after clicked "Reload Accounts". I tried to set it again from /settings, but got an "invalid username" error. Finally I tried a shorter fname and that succeeded.

If there is a character limit on fnames, I suggest displaying that as soon as the user input is invalid.

• Original attempt from /farcaster-# (failed silently): hats-delegator-test1
• First attempt from /settings (failed with error): hats-delegator-test2
• Second attempt from /settings (succeeded): hats-test-1