Custom bones in player armor don't inherit their parent's transformation

*Partner Rank:*

2

*Partner Team Reporting:*

Everbloom Studios

*Verification builds:*

1.13.0.12 and 1.13.0.15_rc1

*Summary:*

Custom bones in player armor geometry, whose parent is a vanilla bone, don't inherit their parent's transformation. This means custom bones in the armor will always appear as if the player was in their default pose, even if their head was rotated or if they were crouching.

*Impact:*

We are unable to cleanly override player armor geometry, something we were able to do for a few builds now.

*Repro Steps:*

1. Create and join the provided world.
2. Go into F5.
3. Look at the mini-helmet above your player's model

*Observed Results:*

The mini-helmet is stuck in place, and doesn't rotate with your head (only with your body). This is very obvious if you turn your head up or down.

*Expected Results:*

The mini-helmet should always follow the player's head rotation and position. The clearest way to see it is by looking straight up. The mini-helmet should be behind the player, not right above.

*Screenshots/Videos attached: Yes/No*

Yes. The first screenshot is the expected behavior, the second screenshot is the bugged behavior.

*Regression Builds:*

1.13.0.9 (Unable to test this in 1.13.0.10 due to its own set of issues with custom player armor, which were fixed in 1.13.0.12)

*Notes:*
A player_armor.json has also been attached, which is an edit of the vanilla file with an extra bone, whose parent is 'head'.