Cloning over _time_created when cloning Experiment

[mgrange1998]

Summary:
Quick RFC for everyone:

This equality check is failing sometimes in Python 3.9 on open source ( T184131441 ):

def test_clone_with(self) -> None:
        experiment = get_experiment()
        cloned_experiment = experiment.clone_with()
        self.assertEqual(cloned_experiment.name, "cloned_experiment_" + experiment.name)
        cloned_experiment._name = experiment.name
        self.assertEqual(cloned_experiment, experiment)

The error is

Experiment(test) (type <class 'ax.core.experiment.Experiment'>) != Experiment(test) (type <class 'ax.core.experiment.Experiment'>).

Fields with different values:

1) _time_created: 
2024-04-01 05:05:13.000613 (type <class 'datetime.datetime'>) 
!= 2024-04-01 05:05:12.998793 (type <class 'datetime.datetime'>).

This is a race condition, where if "get_experiment" and "clone_with" execute quickly the _time_created field will be equal, but if there is delay they'll be unequal.

Proposed fixes:

1. In experiment equality check, ignore "_time_created" field entirely.
2. In experiment equality check, check if the "_time_created" fields are "nearly equal"
3. Set the clone's _time_created field manually to experiment._time_created

I've taken the first approach for this diff, but want to get team feedback on what the preferred approach would be.

Differential Revision: D55596348

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This pull request was exported from Phabricator. Differential Revision: D55596348

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.91%. Comparing base (86a4c8d) to head (e59dcf1).

❗ Current head e59dcf1 differs from pull request most recent head 38772b8. Consider uploading reports for the commit 38772b8 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2307   +/-   ##
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  Coverage   94.91%   94.91%           
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  Files         489      489           
  Lines       47710    47712    +2     
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+ Hits        45282    45284    +2     
  Misses       2428     2428           

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This pull request has been merged in 95bafb0.