[FIR] Report conflicts for data class generated members

^KT-59880

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

@@ -1,6 +1,6 @@
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
-data class A(val x: Int, val y: String) {
+data class <!CONFLICTING_OVERLOADS!>A(val x: Int, val y: String)<!> {
     <!CONFLICTING_OVERLOADS!>fun copy(x: Int, y: String)<!> = x
     <!CONFLICTING_OVERLOADS!>fun copy(x: Int, y: String)<!> = A(x, y)
 }