Add USA₮ and XAU₮ as supported paymaster tokens (DOC-241)

Created by: ihsraham

This PR updates the wallet-evm-erc-4337 configuration documentation to explicitly list USA₮ and XAU₮ as supported tokens for gas payments on Ethereum Mainnet.

Changes

• Modified sdk/wallet-modules/wallet-evm-erc-4337/configuration.md:
  • Added a "Supported Paymaster Tokens" callout box in the "Ethereum Mainnet" section.

Ticket: DOC-241

Verification

• Verified the contract addresses against the ticket (DOC-241) and Etherscan.
• Verified markdown rendering on gitbook.