implement override of toString() in order to print useful message in release...

implement override of toString() in order to print useful message in release mode as well as debug mode (#118263)

Added `_ErrorDescription.toString()`

packages/flutter/lib/src/foundation/assertions.dart

@@ -223,6 +223,13 @@ abstract class _ErrorDiagnostic extends DiagnosticsProperty<List<Object>> {
          level: level,
        );
 
+  @override
+  String toString({
+    TextTreeConfiguration? parentConfiguration,
+    DiagnosticLevel minLevel = DiagnosticLevel.info,
+  }) {
+    return valueToString(parentConfiguration: parentConfiguration);
+  }
 
   @override
   List<Object> get value => super.value!;

packages/flutter/test/foundation/assertions_test.dart

@@ -16,6 +16,13 @@ void main() {
     expect(log[1], contains('debugPrintStack'));
   });
 
+  test('should show message of ErrorDescription', () {
+    const String descriptionMessage = 'This is the message';
+    final ErrorDescription errorDescription = ErrorDescription(descriptionMessage);
+
+    expect(errorDescription.toString(), descriptionMessage);
+  });
+
   test('debugPrintStack', () {
     final List<String> log = captureOutput(() {
       final FlutterErrorDetails details = FlutterErrorDetails(