Most held blocks and items don't cast shadows in first person view (Deferred Technical Preview)

Steps to Reproduce:

1. Create a world with a PBR enabled resource pack and the "Render Dragon Features for Creators" experiment enabled;
2. In first person view, look at the ground and observe your shadow;
3. Grab any block or item.

Observed Results:
With the exception of attachables, any block or item that you hold will make zero changes to the shape of your shadow.

Expected Results:
Any held block or item casts the appropriate shadow.

Notes: Similar to MCPE-177190, but affects every block and is only applicable in first person.