Issue : Mobs can't move/swim when there is mud block underneath.
Expected Results : Mobs can move/swim when there is mud block underneath.

Reproduce Issue :
1.Get a mob that is affected.
2.Put in underwater make sure there is mud block underneath it or search a mangrove biome.
3.As you can see the mobs can't walk/swim underwater.

Mobs Affected :
-Fish
-Axolotl
-Drowned and other hostile mobs that can swim underwater
-Frog and tadpoles.
-Squid and Glow Squid
-Dolphin
-Turtle