handle auto push errors

[dberenbaum]

Fixes Handle case where remote doesn't exist in #10137.

This raises a warning and disables auto push if remote validation fails. Without this PR, it fails early, which is also reasonable, but I think it's less desirable for this scenario. If I set up a new repo and login to Studio, I won't be able to run any experiments until I have a dvc and git remote configured or I disable auto push.

[codecov]

Codecov Report

Attention: Patch coverage is 94.44444% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 90.64%. Comparing base (0001cc3) to head (5dfa676).

Files	Patch %	Lines
dvc/repo/experiments/executor/base.py	90.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10340   +/-   ##
=======================================
  Coverage   90.63%   90.64%           
=======================================
  Files         500      500           
  Lines       38626    38641   +15     
  Branches     5584     5586    +2     
=======================================
+ Hits        35010    35027   +17     
+ Misses       2971     2969    -2     
  Partials      645      645           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.