[Hotfix] Fix failing TestBroadcast on local

[Kourin1996]

Description

This PR fixes the issue in TestBroadcast e2e test. This test uses NewTestServers to start multiple servers but used port is not marked occupied if IP address is not given for JSON-RPC address. then the following servers will use same port.

This PR sets default local IP address for test server in e2e.

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

Please complete this section if any breaking changes have been made, otherwise delete it

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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[zivkovicmilos]

Tested this out and can confirm it works fine 💯

Thank you for going the extra mile to clean up the code a bit, it really makes a difference in the long run 🙏