Setuptools "Package would be ignored"

Description

I haven't looked into this any further, I'm just passing along this warning appearing in the conda-forge CI.

          ********************************************************************************
          ############################
          # Package would be ignored #
          ############################
          Python recognizes 'pytensor.scan' as an importable package[^1],
          but it is absent from setuptools' `packages` configuration.

          This leads to an ambiguous overall configuration. If you want to distribute this
          package, please make sure that 'pytensor.scan' is explicitly added
          to the `packages` configuration field.

          Alternatively, you can also rely on setuptools' discovery methods
          (for example by using `find_namespace_packages(...)`/`find_namespace:`
          instead of `find_packages(...)`/`find:`).

          You can read more about "package discovery" on setuptools documentation page:

          - https://setuptools.pypa.io/en/latest/userguide/package_discovery.html

          If you don't want 'pytensor.scan' to be distributed and are
          already explicitly excluding 'pytensor.scan' via
          `find_namespace_packages(...)/find_namespace` or `find_packages(...)/find`,
          you can try to use `exclude_package_data`, or `include-package-data=False` in
          combination with a more fine grained `package-data` configuration.

          You can read more about "package data files" on setuptools documentation page:

          - https://setuptools.pypa.io/en/latest/userguide/datafiles.html


          [^1]: For Python, any directory (with suitable naming) can be imported,
                even if it does not contain any `.py` files.
                On the other hand, currently there is no concept of package data
                directory, all directories are treated like packages.
          ********************************************************************************

Start by reproducing the warning in the linked conda-forge CI log and inspect the project's setuptools packaging configuration for pytensor.scan. Confirm whether that package should be distributed; done means the warning is resolved or the intended exclusion is explicitly verified.