Sneaking causes incorrect positioning of held items under certain circumstances

Decided to merge a bunch of these tickets into one, since they're more or less an identical issue.

Under certain circumstances while sneaking, the positioning of an item can be miscalculated, causing it to be offset from its intended position on a player. Known examples include:

• held items while sneaking and swimming simultaneously (MC-126436)
• sneaking while aiming a trident (MC-125204)
• items in the offhand (notably shields) while sneaking and charging a bow (MC-87917)
• cast fishing line (MC-4490)