Remove dead definesCustomBuildConfigurations (#56961)

diff --git a/packages/flutter_tools/lib/src/ios/xcodeproj.dart b/packages/flutter_tools/lib/src/ios/xcodeproj.dart
index b2fab77..08f3625 100644
--- a/packages/flutter_tools/lib/src/ios/xcodeproj.dart
+++ b/packages/flutter_tools/lib/src/ios/xcodeproj.dart
@@ -469,11 +469,6 @@
   final List<String> schemes;
 
   bool get definesCustomSchemes => !(schemes.contains('Runner') && schemes.length == 1);
-  bool get definesCustomBuildConfigurations {
-    return !(buildConfigurations.contains('Debug') &&
-        buildConfigurations.contains('Release') &&
-        buildConfigurations.length == 2);
-  }
 
   /// The expected scheme for [buildInfo].
   static String expectedSchemeFor(BuildInfo buildInfo) {