SQLCheckOperator fails if it returns dict with any Falsy values

[spencertollefson]

closes: #34794

This PR modifys the SQLCheckOperator's behaviour in how it handles reading a Python dict.

Previously, if a Python dict was returned by the SQL query, the SQLCheckOperator would always pass. As suggested in the linked issue, if a Python dict is returned it is recommended that if any of the dict's values are False-y , then the Operator should fail. This PR makes that change.

For example, if the SQL query being tested returns:

{'DUPLICATE_ID_CHECK': False, 'NULL_VALUES_CHECK': True}

then the operator should return False, since there is a Falsy value present.

The PR also adds an additional unit test and updated the documentation of the Operator.

Question for reviewers: I am concerned that users may be implementing this operator under the assumption that any dict returned means the task should pass. With this change, that would now lead to the task failing.

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[boring-cyborg]

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[hussein-awala]

For me, it's a bug fix, and there is no breaking change. LGTM

cc: @eladkal

[boring-cyborg]

Awesome work, congrats on your first merged pull request! You are invited to check our Issue Tracker for additional contributions.