Skip gas estimation if already present (ethereum)

[korkoshko]

Description

We don't need call estimateGas if the gas property already present in the serialized transaction.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[korkoshko]

@Hathoriel could you please review this?

[Hathoriel]

Hello @korkoshko
Thank you for your PR.
It looks perfect, but can you please upgrade the package.json version?
After you do it, I will approve and merge this pull request.
Thank you

[korkoshko]

@Hathoriel Done. Thanks!