cache/item: use correct texture brightness

there is some horribleness with it sharing pixel data with the passed in
TextureProvider, but not sharing brightness through it

cache/src/main/java/net/runelite/cache/item/ItemSpriteFactory.java

@@ -109,6 +109,7 @@ else if (item.placeholderTemplateId != -1)
 		}
 
 		RSTextureProvider rsTextureProvider = new RSTextureProvider(textureProvider, spriteProvider);
+		rsTextureProvider.brightness = JagexColor.BRIGHTNESS_MAX;
 
 		SpritePixels spritePixels = new SpritePixels(36, 32);
 		Graphics3D graphics = new Graphics3D(rsTextureProvider);