[MCPE-37671] Guardians can´t spawn in bubble columns

Guardians can´t spawn in bubble columns but every other water mob (drowned, Squid, different types of fish) can spawn in them.

Screen shots shows a guardian tempel before and after placing soulsand.

Linked issues

Confirmed on 1.7.1 / iOS. Guardians seem to spawn only in water source blocks. The direction of bubbles doesn't matter.

While this is technically a parity issue, I don't think it's an intended behavior because no other aquatic mobs behave like this.

Affects 1.10

Still affects 1.11.4

this issue seems to be resolved as of 1.15

Resolving issues that were marked as fixed in the 1.15 and 1.16 Betas, now that 1.16.0 is being released.