Propagate custom Solidity errors for eth_estimateGas JSON RPC function

[jelacamarko]

Description

If a custom error occurs, the result.ReturnValue will represent ABI encoded custom error in the eth_estimateGas JSON RPC function.
The same thing was done through this PR, but only for Call (#1566). This particular PR fixes the eth_estimateGas function and propagates the execution result return value (which should be a hex-encoded custom error in case it reverts with it).

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Breaking changes

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Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

Manual tests

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Documentation update

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Additional comments

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[Stefan-Ethernal]

Generally, it looks good. Tested it manually and the behavior is expected. Could we add some more unit tests maybe?

[Stefan-Ethernal]

LGTM