Fix effectiveGasPrice computation for eth_getTransactionReceipt

[elfedy]

What does it do?

Fixes wrong value for effectiveGasPrice on eth_getTransactionReceipt which is using NextFeeMultiplier from the block the transaction happened vs the NextFeeMultiplier on the previous block which is the actual value used to compute the base fee for the transaction.

Is there something left for follow-up PRs?

There might be other places where gas_price runtime call with the hash of the block is used to get the base fee. Those places should also be updated for the sake of consistency, maybe abstracting the computation of the base fee. Example: https://github.com/moonbeam-foundation/frontier/blob/2f509926db8df03aa6f831d48fcf18a3c456cc49/client/rpc/src/eth/block.rs#L114

What alternative implementations were considered?

eth_getTransactionReceipt rpc call makes a runtime call to moonbeam internally, there is the argument of implementing the fix on moonbeam via that runtime call vs patching frontier.

Are there relevant PRs or issues in other repositories (Substrate, Polkadot, Frontier, Cumulus)?

moonbeam-foundation/frontier#199

What value does it bring to the blockchain users?

RPC users will get the actual effectiveGasPrice used by the transaction.

[github-actions]

Coverage Report

@@                    Coverage Diff                    @@
##           master   elfedy-fix-receipt-gas     +/-   ##
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  Coverage   80.94%                   80.94%   0.00%     
  Files         287                      287             
  Lines       94330                    94330             
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  Hits        76354                    76354             
  Misses      17976                    17976             

Files Changed	Coverage

Coverage generated Fri Jan 12 14:03:00 UTC 2024

[librelois]

Good work @elfedy, the test looks good to me, and it fail properly.
Now you can use your frontier branch with the fix