Non-"attached" hanging signs cannot be placed underneath honey blocks

Summary:
Hanging signs placed underneath honey blocks will always be placed with the "attached" block state set to "true". This is despite the fact that the underside of a honey blocks has sufficient space to support a hanging sign with this state set to "false", as can be seen via use of a debug stick.

Steps to reproduce:

1. Place a honey blocks in the air.
2. Place a hanging sign underneath honey blocks.

Observed results:
It is instead placed with the two chains connected in a Λ-shape.

Expected results:
The hanging sign would be placed in the state with two unconnected chains.