fix timing issue when changing 1D <-> 2D credits to @blazoncek

wled00/set.cpp

@@ -815,8 +815,13 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
       }
     }
     strip.panel.shrink_to_fit();  // release unused memory
+    // we are changing matrix/ledmap geometry which *will* affect existing segments
+    // since we are not in loop() context we must make sure that effects are not running. credit @blazonchek for properly fixing #4911
+    strip.suspend();
+    strip.waitForIt();
     strip.deserializeMap(); // (re)load default ledmap (will also setUpMatrix() if ledmap does not exist)
     strip.makeAutoSegments(true); // force re-creation of segments
+    strip.resume();
   }
   #endif