Clarification of the task and function description

[MagdalenaTyminska]

This PR improves the description of the task and the function is_criticality_balanced().
The task and description of the function did not precisely state that all conditions have to be met so people could think that the function should return True if just one of the conditions was satisfied.
I have added more clarification to the description so there are no doubts what is the correct logic for the function.

[github-actions]

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