Lower severity of "Got invalid timestamp" message

BUG: 459405


(cherry picked from commit d32aebb7)

src/core/renderloop.cpp

@@ -128,10 +128,10 @@ void RenderLoopPrivate::notifyFrameCompleted(std::chrono::nanoseconds timestamp)
     if (lastPresentationTimestamp <= timestamp) {
         lastPresentationTimestamp = timestamp;
     } else {
-        qCWarning(KWIN_CORE,
-                  "Got invalid presentation timestamp: %lld (current %lld)",
-                  static_cast<long long>(timestamp.count()),
-                  static_cast<long long>(lastPresentationTimestamp.count()));
+        qCDebug(KWIN_CORE,
+                "Got invalid presentation timestamp: %lld (current %lld)",
+                static_cast<long long>(timestamp.count()),
+                static_cast<long long>(lastPresentationTimestamp.count()));
         lastPresentationTimestamp = std::chrono::steady_clock::now().time_since_epoch();
     }