refactor: remove duplicate funtion name IsEthereum

[lukema95]

Description

We already have the function IsEthereumChain that has the same function as IsEthereum, so the duplicate function IsEthereum should be removed.

Closes: #1271

Type of change

• Bug fix (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)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Include instructions and any relevant details so others can reproduce.

• Tested CCTX in localnet
• Tested in development environment
• Go unit tests
• Go integration tests
• Tested via GitHub Actions

Checklist:

• I have added unit tests that prove my fix feature works

[lumtis]

Looking good, thanks for the contribution, I see there is a small conflict to resolve

[lukema95]

Looking good, thanks for the contribution, I see there is a small conflict to resolve

Conflict resolved

[lumtis]

Not sure why this gosec got raised now, created a PR for it #1288