Allow Lucky::UploadedFile access in Avram::Params

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Within an operation, after I have passed in my `Lucky::Params` to a create or update method, the `Lucky::Params` get type coerced to `Avram::Params` both classes fulfill the `Avram::Paramable` contract. However, `Lucky::Params` also defines methods for getting a `Lucky::UploadedFile` whereas `Avram::Params` does not.

Adding the `get_file` and `get_file?` methods to the `Avram::Paramable` module could solve this. I also wonder if using the `Avram::Params` as a type of decorator could also help solve this by using a getter for access to `Lucky::Params` if access to that is needed for other methods specific to that class.

Start by tracing Avram::Paramable and Avram::Params where Lucky::Params is coerced during create or update operations. Compare the existing Lucky::Params file-access methods, get_file and get_file?, and determine how they should remain available through the Avram interface; done means uploaded-file access works from those operations without breaking the contract.

Written by the indexing model from the issue text.