Fix personal_sign compatibility issues

[sherardxu]

Compatible with various personal_sign calling methods.

MetaMask Test Dapp

{
    "id": 1669276639299,
    "method": "personal_sign",
    "params":
    [
        "0x4578616d706c652060706572736f6e616c5f7369676e60206d657373616765",
        "0x0000000000000000000000000000000000000000",
        "Example password"
    ]
}

MOBOX

{
    "id": 1669276574176,
    "method": "personal_sign",
    "params":
    [
        "0x0000000000000000000000000000000000000000",
        "wallet_login_27821276"
    ]
}

[Alkhatri77]

{
"id": 1669276574176,
"method": "personal_sign",
"params":
[
"0x0000000000000000000000000000000000000000",
"wallet_login_27821276"
]
}

[Alkhatri77]

src/ethereum_provider.js