Client code in Dart doesn't compile with latest Flutter SDK

Q&A (please complete the following information)

• OS: Windows 10
• Browser: Firefox
• Version: 109.0.1
• Method of installation: [e.g. npm, dist assets] webapp
• Swagger-Editor version: [e.g. 3.10.0]
• Swagger/OpenAPI version: [OpenAPI 3.0]

Content & configuration

-Load the petstore API 3.0

• generate Dart Client code and open it on a system with the latest Flutter /Dart SDK installed

Describe the bug you're encountering

It clearly shows that the generated code isn't compatible with the latest Dart compiler versions. Especially it hasn't be adapted to non nullability of the Dart language, so the code has lots and lots of warnings and errors:

Expected behavior

production of valid Dart code

Additional context or thoughts

depending on how your code generator is implemented I maybe able to help you fix the code
I really like the idea of using SwaggerHub in our company but without valid Dart code it doesn't make sense

Reproduce the issue by loading the Petstore OpenAPI 3.0 definition and generating a Dart client, then open the generated client with the latest Flutter/Dart SDK. Inspect the generated output for null-safety compiler errors; done means the client is valid Dart code that compiles without the reported warnings and errors.