Remove itemstack mutation on player drop method

This appears to cause alot of issues, as the general assumption when calling this method is that the itemstack would not be mutated.

The dupe that this was meant to resolve was patched.

Fixes #11520 / #11765

paper-server/patches/sources/net/minecraft/server/level/ServerPlayer.java.patch

@@ -1399,18 +1399,6 @@
              return itemEntity;
          }
      }
-@@ -1955,6 +_,11 @@
-             return null;
-         } else {
-             double d = this.getEyeY() - 0.3F;
-+            // Paper start
-+            ItemStack tmp = droppedItem.copy();
-+            droppedItem.setCount(0);
-+            droppedItem = tmp;
-+            // Paper end
-             ItemEntity itemEntity = new ItemEntity(this.level(), this.getX(), d, this.getZ(), droppedItem);
-             itemEntity.setPickUpDelay(40);
-             if (includeThrowerName) {
 @@ -2008,6 +_,16 @@
      }