[flutter_tools] hide tree-shake-icons (#56924)

packages/flutter_tools/lib/src/runner/flutter_command.dart

diff --git a/packages/flutter_tools/lib/src/runner/flutter_command.dart b/packages/flutter_tools/lib/src/runner/flutter_command.dart
index 3c5c5df..a658165 100644
--- a/packages/flutter_tools/lib/src/runner/flutter_command.dart
+++ b/packages/flutter_tools/lib/src/runner/flutter_command.dart
@@ -445,6 +445,7 @@
       defaultsTo: enabledByDefault
         ?? kIconTreeShakerEnabledDefault,
       help: 'Tree shake icon fonts so that only glyphs used by the application remain.',
+      hide: true,
     );
   }