Make event values return item stacks instead of item types if possible

[TPGamesNL]

Description

Makes some event values return ItemStacks instead of ItemTypes, since that is more direct.
The issue in #4109 was caused by the event-value getter first converting the ItemStack to an ItemType, and after that it got converted back to an ItemStack, where the reference got lost, as the converter called ItemType#getRandom, which clones the ItemStack.

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Target Minecraft Versions: any
Requirements: none
Related Issues: #4109

[TheLimeGlass]

Haven't we done this in the past and it caused more issues then we could count? I have a feeling that Skript will try to convert and cause the majority of the issues.

[TPGamesNL]

@Wealthyturtle would you be able to weigh in on this (because of #2510)?

[Whimsyturtle]

@Wealthyturtle would you be able to weigh in on this (because of #2510)?

I think this change is fine since it fixes conversion between ItemStack and ItemType (so long as it doesn't break other stuff)

[TPGamesNL]

I think this change is fine since it fixes conversion between ItemStack and ItemType (so long as it doesn't break other stuff)

Well this PR itself doesn't fix any conversion, but there is a ItemStack -> ItemType converter which should do this:

Skript/src/main/java/ch/njol/skript/classes/data/DefaultConverters.java

Lines 206 to 218 in d8b1d52

	Converters.registerConverter(ItemType.class, ItemStack.class, new Converter<ItemType, ItemStack>() {
	@Override
	@Nullable
	public ItemStack convert(final ItemType i) {
	return i.getRandom();
	}
	});
	Converters.registerConverter(ItemStack.class, ItemType.class, new Converter<ItemStack, ItemType>() {
	@Override
	public ItemType convert(final ItemStack i) {
	return new ItemType(i);
	}
	});

But I'm not sure if the converters are always checked, so it could still give issues. If this gets tested properly, it should be fine.

[AyhamAl-Ali]

This change sounds better for me. Hopefully it doesn't break anything unexpectedly

[APickledWalrus]

I think we are fine to trial this out for the 2.7 alphas