fix(repo): git clone output to Stderr

[dangogh]

Description

This ensures that git clone output is directed to os.Stderr instead of os.Stdout. Test added to demonstrate that stdout is empty after clone.

Related issues

• Close fix(repo): git CLI output mangles stdout #7547

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

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[dangogh]

NOTE: currently unable to run mage test:unit due to an error: ../../wasm/sdk.go:146:10: cannot use uintptr(size) (value of type uintptr) as int value in assignment. Probably something due to my macbook pro M3 installlation. I'll bring up in discussions tomorrow if unable to resolve that.