Allow Path in reproject_from_healpix

[AlecThomson]

The docs of reproject_from_healpix state:

def reproject_from_healpix(
    input_data, output_projection, shape_out=None, hdu_in=1, order="bilinear", nested=None, field=0
):
    """
    Reproject data from a HEALPIX projection to a standard projection.

    Parameters
    ----------
    input_data : object
        The input data to reproject. This can be:

            * The name of a HEALPIX FITS file
            * A `~astropy.io.fits.TableHDU` or `~astropy.io.fits.BinTableHDU`
              instance
            * A tuple where the first element is a `~numpy.ndarray` and the
              second element is a `~astropy.coordinates.BaseCoordinateFrame`
              instance or a string alias for a coordinate frame.

However, in the current first branch is only checked in 'The name of a HEALPIX FITS file' is a str type. This is a simple PR to fix the type checking for input_data.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.62%. Comparing base (e62061b) to head (cd9acae).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #625   +/-   ##
=======================================
  Coverage   90.61%   90.62%           
=======================================
  Files          51       51           
  Lines        2429     2431    +2     
=======================================
+ Hits         2201     2203    +2     
  Misses        228      228           

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