Prop 123: Registering `USDC.inj` vat-bank asset

From Core-eval heads-up community discussion:

The proposal is small and narrowly scoped. It registers a single interchain asset:

• Denom: ibc/A7BE5E1F50DE0393383EC287BDD0FDAA9B546736F7511F8E494ECB05533DAAE8
• Issuer name: USDC.inj
• Decimal places: 6