[BUGFIX] DataContextV3.test_yaml_config() should not alter great_expectations.yml (#2136)
[BUGFIX] DataContextV3.test_yaml_config() should not alter great_expectations.yml (#2136)

* DataContextV3.test_yaml_config() should not alter the great_expectations.yml file.

* Cleanup.
great-expectations/great_expectations,great-expectations/great_expectations,great-expectations/great_expectations,great-expectations/great_expectations