While raining, water sensitive mobs to not take damage when inside/next to non-full blocks

The Bug:

Entities that are weak to rain (enderman, blaze, snow golem, strider) will not take damage if standing inside of a non-full block despite being underneath rain fall overhead.

Steps to Reproduce:

Spawn the listed entities above inside of a barrier holding area, and have open trapdoors as high as the entity's hitbox is, like so:

Observed Results:

None of the entities will be damaged.

Expected Results:

The entities would take damage from the rain.

Code Analysis:

This issue shares the same code analysis with MC-265045