in `jp2parser.py` Get image dimensions from jp2 metadata rather than the fits header

[dgarciabriseno]

In the lines referenced below, NAXIS1 represents the width of the image and NAXIS2 represents the height. We can get these dimensions from the jp2 metadata (via glymur.Jp2k) instead of getting them from the fits header (self._data).

api/install/helioviewer/jp2parser.py

Lines 63 to 64 in 8932a79

	image['NAXIS1'] = self._data['NAXIS1'] if 'NAXIS1' in self._data else 'NULL'
	image['NAXIS2'] = self._data['NAXIS2'] if 'NAXIS2' in self._data else 'NULL'