Fixup git fallbacks for #1798 and #1799

[Racer159]

Description

This fixes the git fallback code to do the following:

1. Print the git command for easier reference when debugging git fallback issues
2. Pull all branches / refs when doing a full-repo fallback clone
3. Properly pull a single branch when doing a branch clone

Related Issue

Fixes #1799
Fixes #1798
Fixes #1837

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide Steps followed

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