scm: add cause of clone errors

[dtrifiro]

This will show the cause of clone errors. e.g.

dvc get https://github.com/dberenbaum/example-get-started-cp.git README.md -o deleteme

ERROR: failed to get 'README.md' - SCM error: Failed to clone repo 'https://github.com/dberenbaum/example-get-started-cp.git' to '/tmp/tmp98x3h8g0dvc-clone': No valid credentials provided

related: #8654

[codecov]

Codecov Report

Base: 93.51% // Head: 93.50% // Decreases project coverage by -0.01% ⚠️

Coverage data is based on head (3175369) compared to base (68b2430).
Patch coverage: 33.33% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8746      +/-   ##
==========================================
- Coverage   93.51%   93.50%   -0.02%     
==========================================
  Files         457      457              
  Lines       36195    36203       +8     
  Branches     5242     5244       +2     
==========================================
+ Hits        33848    33850       +2     
- Misses       1839     1845       +6     
  Partials      508      508              

Impacted Files	Coverage Δ
dvc/commands/get.py	86.36% <25.00%> (-6.14%)	⬇️
dvc/commands/imp.py	82.35% <25.00%> (-7.65%)	⬇️
dvc/scm.py	86.61% <100.00%> (ø)

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[dberenbaum]

LGTM, thanks!

[shcheklein]

Thanks! Good improvement.

[dtrifiro]

Looking into the benchmark failures before merging...

[dtrifiro]

Related: treeverse/scmrepo#159