exp list: show experiment shas

[dberenbaum]

• ❗ I have followed the Contributing to DVC checklist.

• 📖 If this PR requires documentation updates, I have created a separate PR (or issue, at least) in dvc.org and linked it here.

Shows experiment SHAs like this:

$ dvc exp list -A
notebook:
        4e8a178 [burnt-sera]
        5cdc6a9 [liked-pees]
        0ec726a [unwed-kana]

Not supported for git remotes, where it continues to show the old format:

$ dvc exp list -A origin
0361ee4:
        extra-hunk

Also adds --sha-only arg (not supported for git remotes), which outputs like:

$ dvc exp list -A --sha-only
f1edf21
1d4c01d
f8f9be7

[dberenbaum]

Not sure if there's an easy way to get the rev of a remote ref. Skipped it here.

[pmrowla]

This is possible to do but it's not implemented right now in scmrepo, we can add it in the future if it's actually needed

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.02 🎉

Comparison is base (79c8800) 91.16% compared to head (4618b6c) 91.18%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9501      +/-   ##
==========================================
+ Coverage   91.16%   91.18%   +0.02%     
==========================================
  Files         474      474              
  Lines       36692    36731      +39     
  Branches     5226     5233       +7     
==========================================
+ Hits        33449    33494      +45     
+ Misses       2686     2681       -5     
+ Partials      557      556       -1     

Impacted Files	Coverage Δ
tests/func/experiments/test_remote.py	100.00% <ø> (ø)
dvc/commands/experiments/ls.py	100.00% <100.00%> (+24.00%)	⬆️
dvc/repo/experiments/ls.py	100.00% <100.00%> (ø)
tests/func/experiments/test_experiments.py	100.00% <100.00%> (ø)
tests/func/experiments/test_save.py	100.00% <100.00%> (ø)
tests/unit/command/test_experiments.py	100.00% <100.00%> (ø)

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