[flutter_tools] surface null safety/experiment flags in attach (#60317)

Missed this one. Needed for google3 and add2app workflows

packages/flutter_tools/lib/src/commands/attach.dart

@@ -63,6 +63,8 @@ class AttachCommand extends FlutterCommand {
     usesFuchsiaOptions(hide: !verboseHelp);
     usesDartDefineOption();
     usesDeviceUserOption();
+    addEnableExperimentation(hide: !verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     argParser
       ..addOption(
         'debug-port',

packages/flutter_tools/test/general.shard/commands/build_test.dart

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:args/args.dart';
-import 'package:flutter_tools/src/commands/build.dart';
+import 'package:flutter_tools/src/commands/attach.dart';
 import 'package:flutter_tools/src/commands/build_aar.dart';
 import 'package:flutter_tools/src/commands/build_apk.dart';
 import 'package:flutter_tools/src/commands/build_appbundle.dart';
@@ -15,13 +15,14 @@ import 'package:flutter_tools/src/commands/build_macos.dart';
 import 'package:flutter_tools/src/commands/build_web.dart';
 import 'package:flutter_tools/src/commands/build_windows.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
+import 'package:flutter_tools/src/runner/flutter_command.dart';
 
 import '../../src/common.dart';
 import '../../src/context.dart';
 
 void main() {
   testUsingContext('All build commands support null safety options', () {
-    final List<BuildSubCommand> commands = <BuildSubCommand>[
+    final List<FlutterCommand> commands = <FlutterCommand>[
       BuildWindowsCommand(verboseHelp: false),
       BuildLinuxCommand(verboseHelp: false),
       BuildMacosCommand(verboseHelp: false),
@@ -32,9 +33,10 @@ void main() {
       BuildFuchsiaCommand(verboseHelp: false),
       BuildAarCommand(verboseHelp: false),
       BuildIOSFrameworkCommand(verboseHelp: false, buildSystem: globals.buildSystem),
+      AttachCommand(verboseHelp: false),
     ];
 
-    for (final BuildSubCommand command in commands) {
+    for (final FlutterCommand command in commands) {
       final ArgResults results = command.argParser.parse(<String>[
         '--sound-null-safety',
         '--enable-experiment=non-nullable',