T1741

This diff extends the pattern of passing loading status to the App.js component used in D9872 to the Tokens.js screen.

In addition, there was a bug on token creation where the loading status did not clear after successful token mints. This is patched.

An artifact comment is also removed.

npm start, navigate to Tokens, create a token, notice that full UI locks while mint tx is being broadcast, notice that full UI is unlocked after tx is complete.