Mobs which do not take fall damage still do not use the minecraft:generic.fall_damage_multiplier attribute as expected

The bug

Despite MC-270116, a ticket which MC-270248 was resolved as a duplicate of, explicitly listing all of these mobs and being marked as fixed, the issue does not appear to be fixed for them at all.

Affected mobs

• minecraft:allay
• minecraft:bat
• minecraft:bee
• minecraft:blaze
• minecraft:cat
• minecraft:chicken
• minecraft:ghast
• minecraft:iron_golen
• minecraft:magma_cube
• minecraft:ocelot
• minecraft:parrot
• minecraft:phantom
• minecraft:shulker
• minecraft:snow_golem
• minecraft:wither

How to reproduce

1. Summon a chicken
2. Use the /attribute command to obtain its fall damage multiplier attribute

   /attribute @e[type=minecraft:chicken,limit=1] minecraft:generic.fall_damage_multiplier get

Expected results

It would be 0.0 by default.

Actual results

It is 1.0.

How to fix

Get rid of the "fall damage immune" entity types tag, and convert all existing mobs within it over correctly by setting their fall damage multiplier attribute to 0.0. All newly spawned such mobs should have their fall damage immune attribute at 0.0.