Revert "[FIR] Let attributes opt-in to participating in ConeClassLikeTypeImpl structural equality"

This reverts commit 9189154cae.

compiler/testData/codegen/box/casts/mutableCollections/reifiedIsWithMutable.jvm_abi.txt

@@ -1,4 +1,18 @@
 MODULE main
+	CLASS MLItr.class
+		CLASS METADATA
+			FUNCTION add(Ljava/lang/String;)V
+				Property: class.metadata.function.valueParameters
+					K1
+						(element: kotlin/String)
+					K2
+						(element: @kotlin/jvm/internal/EnhancedNullability kotlin/String)
+			FUNCTION set(Ljava/lang/String;)V
+				Property: class.metadata.function.valueParameters
+					K1
+						(element: kotlin/String)
+					K2
+						(element: @kotlin/jvm/internal/EnhancedNullability kotlin/String)
 	CLASS C.class
 		CLASS METADATA
 			K1