`namada_sdk::rpc::get_token_balance()` returns 0 due to empty response at epoch boundary

[bengtlofgren]

The relevant lines are in https://github.com/anoma/namada/blob/main/sdk/src/queries/vp/token.rs#L37

Interestingly enough, this function only gets called from the CLI when you run namadac balance --owner <owner> but otherwise is not used.

Surprisingly, the cli implementation somehow works around this issue by waiting until the epoch boundary has passed and then returning the correct balances.