place trapdoors on block above -> trapdoor is on bottom half

What happened?
The trapdoor was placed as a bottom-half trapdoor.

What did I expect to happen?
The trapdoor should have been placed as a top-half trapdoor.

Steps to reproduce the issue:

• Set a block about 3 blocks above the player.
• Place a trapdoor on that block.
• See that the half-tag says "bottom" instead of "top"