no offhand updated

Updated version of Battt's No Offhand Datapack

Changes:

• Updated to version 1.21.4
• Removed bug where items are deleted rather than being returned to inventory after being placed in the offhand
• Removed a visual bug when placing items into offhand while having a GUI open
• Placing items into the offhand while having a full inventory will now drop them to be picked up rather than deleting them