chore: revert "refactor(cli/unstable): string based `ProgressBar` tests (#6679)"

[kt3k]

This reverts commit e10c71ad0cf2d10af443f5de54da985899a934e3 which introduced some flakiness in CI

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.71%. Comparing base (e10c71a) to head (08cfbeb). Report is 17 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6684   +/-   ##
=======================================
  Coverage   94.71%   94.71%           
=======================================
  Files         567      567           
  Lines       46778    46778           
  Branches     6582     6582           
=======================================
+ Hits        44305    44306    +1     
+ Misses       2431     2430    -1     
  Partials       42       42           

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[kt3k]

This is no longer necessary as we chose to use FakeTime for reducing flakiness. https://github.com/denoland/std/pull/6686