Remove --disable-service-auth-codes (flutter#45356)

Discovered by a leakage as described in flutter/flutter#133824, this arg has likely been removed by Dart. Removing this arg eliminates the leakage warning.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

runtime/dart_vm.cc

@@ -90,10 +90,6 @@ static const char* kDartStartPausedArgs[]{
     "--pause_isolates_on_start",
 };
 
-static const char* kDartDisableServiceAuthCodesArgs[]{
-    "--disable-service-auth-codes",
-};
-
 static const char* kDartEndlessTraceBufferArgs[]{
     "--timeline_recorder=endless",
 };
@@ -380,11 +376,6 @@ DartVM::DartVM(const std::shared_ptr<const DartVMData>& vm_data,
     PushBackAll(&args, kDartStartPausedArgs, fml::size(kDartStartPausedArgs));
   }
 
-  if (settings_.disable_service_auth_codes) {
-    PushBackAll(&args, kDartDisableServiceAuthCodesArgs,
-                fml::size(kDartDisableServiceAuthCodesArgs));
-  }
-
   if (settings_.endless_trace_buffer || settings_.trace_startup) {
     // If we are tracing startup, make sure the trace buffer is endless so we
     // don't lose early traces.