[FIR] Use idRenderer to render ClassId in qualifiers

It shouldn't break existing usages, because
1) default `ConeIdRendererForDebugging` renders ClassId in
same way as before the change;
2) I didn't find any usages, which use non-default idRenderer,
but rely on full ClassId be rendered for qualifiers.

^KT-62585

compiler/fir/tree/src/org/jetbrains/kotlin/fir/renderer/FirRenderer.kt

@@ -1183,7 +1183,7 @@ class FirRenderer(
             print("Q|")
             val classId = resolvedQualifier.classId
             if (classId != null) {
-                print(classId.asString())
+                idRenderer.renderClassId(classId)
             } else {
                 print(resolvedQualifier.packageFqName.asString().replace(".", "/"))
             }