Fix custom dimension skybox (1.21.11 regression)

[LCLPYT]

The end shader is no longer used for custom dimensions with the end skybox.

This was caused because of a change in the 1.21.11 upgrade in commit 7f17ac4 in Iris::getCurrentDimension:

-			ResourceLocation effects = level.dimensionType().effectsLocation();
+			Identifier effects = level.dimension().identifier();

This broke the previous patch from PR #2853

In 1.21.11, the effectsLocation() property is now called skybox() and now returns a Skybox enum constant. Possible values are: NONE, OVERWORLD and END

This PR updates the dimension overwrite for the END and OVERWORLD skyboxes. As there is no nether skybox option, the nether overwrite was removed.

Closes #2200

Updated datapack for testing: iris_bug_demo.zip

[TehBrian]

Could this end up somehow being fixed for the nether as well? I'm on 26.2 and experiencing that popular shaders (Bliss, BSL, Complementary) are using overworld effects for my custom nether dimension type.

[LCLPYT]

I have the same problem with one of my dimensions.
Afaik, there is no simple marker that a dimension is using the same settings as the nether anymore.
In the past, there were these "effects" but those were removed in favor of individual aspects such as the skybox etc.

This fix currently only looks at the value for the skybox, as that is as close as a marker as I could find.
Sadly, there is no skybox for the nether, only one for the overworld and one for the nether...

I guess you could somehow check if the dimension settings are similar to those of the nether and use that as an indicator. However its not really that straightforward anymore I think...

[TehBrian]

Maybe it'd be a good idea to recommend to shaderpack authors to check for *:*nether* (though I'm not sure that syntax is supported) in their dimension.properties rather than specifically minecraft:the_nether.

Would it be a bad idea to assume that the none skybox correlates to the nether? That's true for vanilla, at least.

This may be dumb, but in dimension types, cardinal_light has options default and nether. Could it be safe to assume that nether indicates that the world is intended to be nether-esque?

If only there were some way to communicate arbitrary data in dimension types. Maybe the name (*:*nether*) is as close as we can get.

[TehBrian]

Would it be a bad idea to assume that the none skybox correlates to the nether? That's true for vanilla, at least.

This may be dumb, but in dimension types, cardinal_light has options default and nether. Could it be safe to assume that nether indicates that the world is intended to be nether-esque?

Implemented in #3276 :D