Function validateAndExtractApproval

validateAndExtractApproval(
    extensions: Record<string, unknown>,
    extensionInfo: ERC20ApprovalGasSponsorExtensionInfo,
): ERC20ApprovalGasSponsorValidationResult & {
    payload?: ERC20ApprovalGasSponsorPayload;
}
Validates and extracts the ERC-20 approval gas sponsor payload in one step.

This is a convenience function for facilitators that combines extraction and validation against the server's extension info.
Parameters
- extensions: Record<string, unknown>
  The extensions map from a PaymentPayload
- extensionInfo: ERC20ApprovalGasSponsorExtensionInfo
  The server's gas sponsor extension info
Returns ERC20ApprovalGasSponsorValidationResult & {
payload?: ERC20ApprovalGasSponsorPayload;
}
Validation result with the extracted payload if valid
Example
```
const result = validateAndExtractApproval(
  paymentPayload.extensions,
  extensionInfo
);
if (result.valid && result.payload) {
  // Broadcast approval tx, then settle
}
```
- Defined in extensions/src/erc20-approval-gas-sponsoring/facilitator.ts:134