[FIR] Report conflicts for data class generated members

^KT-59880

compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyNoDefaults.fir.kt

@@ -4,6 +4,6 @@ interface WithCopy<T> {
     fun copy(str: T): WithCopy<T>
 }
 
-<!DATA_CLASS_OVERRIDE_DEFAULT_VALUES!>data<!> class Test(val str: String) : WithCopy<String> {
-    override fun copy(str: String) = Test(str)
+<!DATA_CLASS_OVERRIDE_DEFAULT_VALUES!>data<!> class <!CONFLICTING_OVERLOADS!>Test(val str: String)<!> : WithCopy<String> {
+    <!CONFLICTING_OVERLOADS!>override fun copy(str: String)<!> = Test(str)
 }