Warn when build number and version can't be parsed on iOS (#40611)

diff --git a/packages/flutter_tools/test/general.shard/build_info_test.dart b/packages/flutter_tools/test/general.shard/build_info_test.dart
index 1f12d08..d404696 100644
--- a/packages/flutter_tools/test/general.shard/build_info_test.dart
+++ b/packages/flutter_tools/test/general.shard/build_info_test.dart
@@ -16,7 +16,7 @@
 
     testUsingContext('CFBundleVersion for iOS', () async {
       String buildName = validatedBuildNumberForPlatform(TargetPlatform.ios, 'xyz');
-      expect(buildName, '0');
+      expect(buildName, isNull);
       buildName = validatedBuildNumberForPlatform(TargetPlatform.ios, '0.0.1');
       expect(buildName, '0.0.1');
       buildName = validatedBuildNumberForPlatform(TargetPlatform.ios, '123.xyz');
@@ -38,7 +38,7 @@
 
     testUsingContext('CFBundleShortVersionString for iOS', () async {
       String buildName = validatedBuildNameForPlatform(TargetPlatform.ios, 'xyz');
-      expect(buildName, '0.0.0');
+      expect(buildName, isNull);
       buildName = validatedBuildNameForPlatform(TargetPlatform.ios, '0.0.1');
       expect(buildName, '0.0.1');
       buildName = validatedBuildNameForPlatform(TargetPlatform.ios, '123.456.xyz');