[1.16.5] Fix shaders breaking almost every overlay that uses textures, fixes #7575 (#7624)

src/test/java/net/minecraftforge/debug/client/rendering/ShaderFixTest.java

@@ -0,0 +1,20 @@
+package net.minecraftforge.debug.client.rendering;
+
+import net.minecraft.client.entity.player.ClientPlayerEntity;
+import net.minecraft.util.ResourceLocation;
+import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.eventbus.api.SubscribeEvent;
+import net.minecraftforge.fml.client.registry.ClientRegistry;
+import net.minecraftforge.fml.common.Mod;
+import net.minecraftforge.fml.event.lifecycle.FMLClientSetupEvent;
+
+@Mod("shader_fix_test")
+@Mod.EventBusSubscriber(value = Dist.CLIENT, bus = Mod.EventBusSubscriber.Bus.MOD)
+public class ShaderFixTest
+{
+    @SubscribeEvent
+    public static void clientSetup(final FMLClientSetupEvent event)
+    {
+        ClientRegistry.registerEntityShader(ClientPlayerEntity.class, new ResourceLocation("shaders/post/desaturate.json"));
+    }
+}