[flutter_tool] Improve iOS mDNS failure error message (#47348)

packages/flutter_tools/lib/src/mdns_discovery.dart

@@ -193,7 +193,9 @@ class MDnsObservatoryDiscovery {
         UsageEvent('ios-mdns', 'no-ipv4-link-local').send();
         printError(
           'The mDNS query for an attached iOS device failed. It may '
-          'be necessary to disable the "Personal Hotspot" on the device. '
+          'be necessary to disable the "Personal Hotspot" on the device, and '
+          'to ensure that the "Disable unless needed" setting is unchecked '
+          'under System Preferences > Network > iPhone USB.'
           'See https://github.com/flutter/flutter/issues/46698 for details.'
         );
         break;