Wrong texture used for Tripwire hook with string block

Verification builds:
#332621

Summary:
Iron texture is used for tripwire hook string in block model

Impact:
Weird looking block. It impacts quality and can't be fixed by content creator. Would be nice to fix.

Repro Steps:
1. Put 2 tripwire hooks in world
2. Put strings between
3. Look closely at string part of tripwire hook block model

Observed Results:
The texture used for the string in tripwire hook block model is the iron texture instead of string texture. This is particularly visible with PureBDcraft.

Expected Results:
String texture to be used in tripwire hook model

Screenshots/Videos attached: Yes