rename function doCall and doEstimateGas

[gzliudan]

Proposed changes

This PR refactor functions about eth_call and eth_estimateGas:

1. change func (s *PublicBlockChainAPI) doCall to func DoCall.
2. change func (s *PublicBlockChainAPI) doEstimateGas to func DoEstimateGas.
3. change b.BlockByNumber(ctx, rpc.LatestBlockNumber) to b.BlockByNumberOrHash(ctx, blockNrOrHash) in function DoEstimateGas to support all blocks.

Types of changes

What types of changes does your code introduce to XDC network?
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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)
• Regular KTLO or any of the maintaince work. e.g code style
• CICD Improvement

Impacted Components

Which part of the codebase this PR will touch base on,

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• Consensus
• Account
• Network
• Geth
• Smart Contract
• External components
• Not sure (Please specify below)

Checklist

Put an ✅ in the boxes once you have confirmed below actions (or provide reasons on not doing so) that

• This PR has sufficient test coverage (unit/integration test) OR I have provided reason in the PR description for not having test coverage
• Provide an end-to-end test plan in the PR description on how to manually test it on the devnet/testnet.
• Tested the backwards compatibility.
• Tested with XDC nodes running this version co-exist with those running the previous version.
• Relevant documentation has been updated as part of this PR
• N/A