Blocks with different damage values stack when obtained as items if there are no default variants of the block

Blocks with no damage value variants obtained as items stack in the first available stack, even if they have a different damage value.

If you use a damage value of 1 first, they all stack using a missing model.

Steps to reproduce:

1. Give yourself a brown mushroom block using /give @p brown_mushroom_block 1 1
2. Notice it appears as a purple and black checkerboard.
3. Give yourself a brown mushroom block using /give @p brown_mushroom_block 1 0
4. Notice it stacks, and has the missing model
5. Clear your inventory
6. Give yourself a brown mushroom block using /give @p brown_mushroom_block 1 0
7. Notice it looks fine
8. Give yourself a brown mushroom block using /give @p brown_mushroom_block 1 1
9. Notice it stacks and looks fine