addr_sync: get_balance change cache_key to have delimiters
addr_sync: get_balance change cache_key to have delimiters

re https://github.com/spesmilo/electrum/pull/7807/files#r870482609

pooler/electrum-ltc,spesmilo/electrum,spesmilo/electrum,pooler/electrum-ltc,pooler/electrum-ltc,spesmilo/electrum,spesmilo/electrum,pooler/electrum-ltc