refactor: change the way action filter checks custom attribute in controller

[alshuriga]

I've changed the way of mvc action filter checking if controller has FluentValidationAutoValidation attribute.
Tested it in WeatherForecast (dotnet webapi template app) and it seems to work fine.

[mvdgun]

@alshuriga thanks for your contribution! I am seeing some binary files in your PR, perhaps some artifacts from your IDE? Could you remove those? I've marked those files for you.

[mvdgun]

Looking back at the code I think the annotations on methods will break since it only retrieves annotations on the type. Did you test putting an annotation on a controller method?

[alshuriga]

Looking back at the code I think the annotations on methods will break since it only retrieves annotations on the type. Did you test putting an annotation on a controller method?

thank you for noticing that, it works now for both controller and action annotation.

[mvdgun]

@alshuriga I'm still debating whether this change will have a detrimental impact on performance since it uses reflection. Where possible I would like to avoid using reflection. I'm going to look into the EndpointMetadata some more. Maybe .NET offers some public API's that expose the applied attributes.

[alshuriga]

@mvdgun Yes, GetCustomAttribute actually does impact performance if called every request. I found another way to retrieve attributes, it actually seems to work very similar to the original logic, but there's no restrictions in the documentation for using it in application code. Please take a look.

[mvdgun]

@alshuriga Looks like a great option! I have added some remarks.

[mvdgun]

Closes #4

[mvdgun]

Merged, thanks for you contribution @alshuriga!