dont set value if it is a stack trace

dart/lib/src/sentry_exception_factory.dart

@@ -3,6 +3,7 @@ import 'protocol.dart';
 import 'sentry_options.dart';
 import 'sentry_stack_trace_factory.dart';
 import 'throwable_mechanism.dart';
+import 'utils/stack_trace_utils.dart';
 
 /// class to convert Dart Error and exception to SentryException
 class SentryExceptionFactory {
@@ -57,11 +58,13 @@ class SentryExceptionFactory {
       }
     }
 
+    final throwableString = throwable.toString();
+
     // if --obfuscate feature is enabled, 'type' won't be human readable.
     // https://flutter.dev/docs/deployment/obfuscate#caveat
     return SentryException(
       type: (throwable.runtimeType).toString(),
-      value: throwable.toString(),
+      value: throwableString.isStackTrace() ? null : throwableString,
       mechanism: mechanism,
       stackTrace: sentryStackTrace,
       throwable: throwable,

dart/test/sentry_exception_factory_test.dart

@@ -169,6 +169,13 @@ void main() {
 
     expect(sentryException.throwable, throwable);
   });
+
+  test('should not assigns stackTrace string to value', () {
+    final stackTraceError = StackTraceError();
+    final sentryException =
+        fixture.getSut().getSentryException(stackTraceError);
+    expect(sentryException.value, isNull);
+  });
 }
 
 class CustomError extends Error {}
@@ -187,6 +194,17 @@ class CustomExceptionStackTraceExtractor
   }
 }
 
+class StackTraceError extends Error {
+  @override
+  String toString() {
+    return '''
+#0      baz (file:///pathto/test.dart:50:3)
+<asynchronous suspension>
+#1      bar (file:///pathto/test.dart:46:9)
+    ''';
+  }
+}
+
 class Fixture {
   final options = SentryOptions(dsn: fakeDsn);