feat(txpool): use GasFeeCapIntCmp to check min fee

[Thegaram]

1. Purpose or design rationale of this PR

Assuming we set L2GETH_MIN_GAS_PRICE to 48700001 (min base fee + 1), we can now accept transactions with 1 wei tip.

Previously, L2GETH_MIN_GAS_PRICE = 48700001 would have set the minimum tip, but L2GETH_MIN_GAS_PRICE = 1 would have allowed unexecutable legacy txs with 1 wei gas price to enter the txpool.

A motivating example with L2GETH_MIN_GAS_PRICE = 48700001 and baseFee = 48700000:

	effectiveGasTipCapCmp	gasTipCapCmp	gasFeeCapCmp
legacy gasPrice = 1	reject	reject	reject
legacy gasPrice=48700001	reject (1)	accept	accept
1559 gasFeeCap = 48700001, gasTipCap = 1	reject	reject (2)	accept

The previous PR (#825) fixed (1), while this PR aims to fix (2).

2. PR title

Your PR title must follow conventional commits (as we are doing squash merge for each PR), so it must start with one of the following types:

• feat: A new feature

3. Deployment tag versioning

Has the version in params/version.go been updated?

• This PR doesn't involve a new deployment, git tag, docker image tag, and it doesn't affect traces
• Yes

4. Breaking change label

Does this PR have the breaking-change label?

• This PR is not a breaking change
• Yes