Pale oak trees cannot grow on moss blocks

Relates to MCPE-187322

Pale oak trees cannot grow (they can be planted) on moss blocks in Bedrock edition. This is not only a parity issue, but inconsistent with every other tree in the game.

The issue can be fixed by adding a "dirt" tag to the "may_grow_on" component like with the cherry tree, or as with all the other trees, simply add the "minecraft:moss_block" ID to the list of blocks it may grow on.

Steps to reproduce:

1. Plant 4 pale oak saplings in a 2x2 formation on moss blocks.
2. Set the randomtickspeed to 4000.
3. Try bonemealing them.

Observed results:
The tree won't grow.

Expected results:
The tree grows.