There are no shadows on text displayed within signs or sign interfaces

The Bug:

There are no shadows on text displayed within signs or sign interfaces.

The report was created based on this comment by [Mojang] slicedlime.

Steps to Reproduce:

1. Place down a sign and write some text on it.
2. Look closely at the text.

Observed Behavior:

There are no shadows.

Expected Behavior:

There would be shadows.