Add support for Laravel's fluent File validation rule

[squiaios]

Adds support for the Illuminate\Validation\Rules\File validation rule.

With this change, it now correctly transforms the fluent File rule (and ImageFile) into OpenAPI schema definitions. (https://laravel.com/docs/13.x/validation#validating-files)

This ensures that constraints like file types, minimum/maximum sizes, and image dimensions are accurately reflected in the generated documentation.

[romalytvynenko]

@squiaios is this PR created by AI?

[squiaios]

Hello, only the line (fn () => $this->buildValidationRules())->call($rule), was made by AI to resolve the binding issue on protected function, otherwise it's by myself

[romalytvynenko]

I'm not sure I'm following how and why it works. Also why existing rules documentation API is not working here? (see how enum and other rules are implemented)