Tall seagrass can now generate when bone mealing one-high water

Using bone meal on a block with a depth of one block of water now generates seagrass two blocks high. This will also generate water where it should not normally be generated.

Steps to reproduce:

1. Find a place where the water is 1 block deep (where there is only 1 block of water above the block)
2. Use bone meal at this location

Observed result:
Sometimes, fully waterlogged tall seagrass is generated.

Expected result:
Only one block high seagrass should be generated as in 1.21.1 and below.