There should be an option to process TYPE_CHECKING

### Things to check first

- [X] I have searched the existing issues and didn't find my feature already requested there

### Feature description

It would be nice for `typeguard` to actually process what's inside the `if TYPE_CHECKING` blocks, actually importing the referenced modules etc.

It would be nice to have an option to turn on this behavior.

### Use case

That's not how an app would work without `typeguard`, but that would allow to check the app for type correctness more thoroughly.