Describe the bug
eth_signTypedData_v3 params are not as defined in the spec https://github.com/ethereum/EIPs/blob/master/EIPS/eip-712.md#specification-of-the-eth_signtypeddata-json-rpc

To Reproduce
Call

const signedTypedData = {
    jsonrpc: '2.0',
    method: 'eth_signTypedData_v3',
    params: [sender, typedData],
    id: Date.now(),
}

this will error as MetaMask expects the params to be an object

Expected behavior
MetaMask should accept an array with 2 elements (signer, data).