CrossAxisAlignment.baseline is missing from cross axis selection options in Layout Explorer

[albertusdev]

During my internship, I didn't get to implement the logic for visualizing CrossAxisAlignment.baseline because more often than not the baseline of the Flex widget would be null and triggering the change to baseline would trigger an error.

This issue is related to #1610, once #1610 is resolved, we can consider adding CrossAxisAlignment.baseline on the baseline?