fix: wallet balance metric occasionally reporting false 0 amounts

[boojamya]

Our infra team has reported that occasionally the cosmos_relayer_wallet_balance metric falsely reports a balance of 0.

I believe the main culprit here is the ccp.chainProvider.QueryBalance method.

Prior to this PR, we would continue to update the metric even though querying the balance failed.

[jtieri]

good catch here, also definitely prefer to pass errors up to the call site instead of logging them and doing nothing like we were before.