Change from using `defaults` to `plutil` for Plist parsing (#38662)

We were using the `defaults` command-line utility to parse
Plist files, but it was never supported by Apple, and it
appears that in an upcoming OS release, it will be less likely
to work:

> WARNING: The defaults command will be changed in an upcoming
> major release to only operate on preferences domains. General
> plist manipulation utilities will be folded into a different
> command-line program.

Fixes https://github.com/flutter/flutter/issues/37701

packages/flutter_tools/lib/src/ios/simulators.dart

diff --git a/packages/flutter_tools/lib/src/ios/simulators.dart b/packages/flutter_tools/lib/src/ios/simulators.dart
index 043f651..ad46f6d 100644
--- a/packages/flutter_tools/lib/src/ios/simulators.dart
+++ b/packages/flutter_tools/lib/src/ios/simulators.dart
@@ -24,7 +24,7 @@
 import '../protocol_discovery.dart';
 import 'ios_workflow.dart';
 import 'mac.dart';
-import 'plist_utils.dart';
+import 'plist_parser.dart';
 
 const String _xcrunPath = '/usr/bin/xcrun';
 const String iosSimulatorId = 'apple_ios_simulator';
@@ -379,7 +379,7 @@
       // parsing the xcodeproj or configuration files.
       // See https://github.com/flutter/flutter/issues/31037 for more information.
       final String plistPath = fs.path.join(package.simulatorBundlePath, 'Info.plist');
-      final String bundleIdentifier = iosWorkflow.getPlistValueFromFile(plistPath, kCFBundleIdentifierKey);
+      final String bundleIdentifier = PlistParser.instance.getValueFromFile(plistPath, PlistParser.kCFBundleIdentifierKey);
 
       await SimControl.instance.launch(id, bundleIdentifier, args);
     } catch (error) {