Upgrade polygonAmoy's native token from MATIC to POL

[roylines]

This is the same argument as discussed in #2698. In that case the commit was referring to the Polygon mainnet. The same changes have occured to the amoy testnet and a similar change is required.

This file would need the references to MATIC to change to POL
https://github.com/wevm/viem/blob/main/src/chains/definitions/polygonAmoy.ts