Implement auto-consolidation flow

[arboleya]

Follow-up after:

• UTXO Consolidation Helpers #3645

The PR must also be based on:

• feat: UTXO consolidation #3717

Tasks:

• Implement auto-detection to decide when UTXO consolidation is necessary. This must evaluate errors from assembleTx, but to distinguish between insufficient balances and too many coins we may have to fetch user balances for baser asset ID, and if this is non-negotiable, we may just as well fetch balances for base asset within the same HTTP/GQL call that we submit the assembleTx operation.

• When the above is true, consolidation transactions must be sent with the original transaction via the JSON RPC interface under a consolidationTxs property or similar.