ref(dependencies): Improving error handling for dependency logic

[IanWoodard]

https://getsentry.atlassian.net/browse/DEVINFRA-598. Adding additional error handling to the core dependency logic. Fixed the _run_command function to now properly propagate the stderr which it did not do previously which should now give us more information into the failures we see. For now I opted not to add retries to anything besides fetch since fetch is by far the most likely to face transient errors, and retrying certain other commands can put us in a potentially problematic state.
More improvements to the core dependency logic, specifically around the git config are coming in another PR.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.67%. Comparing base (df61e38) to head (a2387bb).
Report is 1 commits behind head on main.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #215      +/-   ##
==========================================
+ Coverage   92.58%   92.67%   +0.08%     
==========================================
  Files          22       22              
  Lines        1578     1597      +19     
==========================================
+ Hits         1461     1480      +19     
  Misses        117      117              

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