[explorer] Remove "Address is empty" message.

Summary:
It's redundant, since it already displays a balance of 0 above

Also, the previous message is slightly confusing, as it could have tokens so not really empty

Also remove the divider in the case where there are no coins listed here.

Test Plan: Run it locally, check various addresses with and without coins and tokens

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D16309