[explorer] Unfold the token balances by default if there is any
Summary: So that the address page shows all the balances upon opening with no additional click required.
Test Plan: Open an address with some tokens and check the balances are unfolded by default.
Reviewers: #bitcoin_abc, PiRK
Reviewed By: #bitcoin_abc, PiRK
Differential Revision: https://reviews.bitcoinabc.org/D16305