Add warning for unnecessarily high gas limit

[Thegaram]

What problem are you trying to solve?

In Ethereum, gas provided but not used by the execution is refunded. In Conflux, on the other hand, we refund at most 25% of the overall gas cost. As this might surprise many users who come from Ethereum, I suggest we add a warning if a user sets gas price to a much higher value than the latest estimate.

Describe the solution you'd like

When Conflux Portal has an estimate available, I suggest we give a warning when the estimated gas charged is larger than gas used by the execution.

Additional context

Here's an example:

gas limit: 1000000
gas price: 10
=> max price: 10000000

gas used: 22339
gas fee: 7500000 (75% of max price)

curl -X POST --data '{"jsonrpc":"2.0","method":"cfx_getTransactionByHash","params":["0x42bfc5b8e21a933d8a2340b75675c6487573673e46c9a0e1683415a7d7bc60fe"],"id":1}' -H "Content-Type: application/json" http://mainnet-jsonrpc.conflux-chain.org:12537

{
    "jsonrpc": "2.0",
    "result": {
        "jsonrpc": "2.0",
        "result": {
            "gas": "0xf4240",
            "gasPrice": "0xa",
            ...
        },
        "id": 1
    }
}

curl -X POST --data '{"jsonrpc":"2.0","method":"cfx_getTransactionReceipt","params":["0x42bfc5b8e21a933d8a2340b75675c6487573673e46c9a0e1683415a7d7bc60fe"],"id":1}' -H "Content-Type: application/json" http://mainnet-jsonrpc.conflux-chain.org:12537

{
    "jsonrpc": "2.0",
    "result": {
        "gasFee": "0x7270e0",
        "gasUsed": "0x5743",
        ...
    },
    "id": 1
}

[lionking062]

Good issue. We'll perfect it.

[yqrashawn]

https://app.clickup.com/t/51uf6u