Fix imports after rebase

Author: mwcraig

src/astro_image_display_api/dummy_viewer.py

@@ -1,7 +1,7 @@
 import numbers
 import os
 from collections import defaultdict
-from copy import deepcopy
+from copy import copy, deepcopy
 from dataclasses import dataclass, field
 from pathlib import Path
 from typing import Any

src/astro_image_display_api/widget_api_test.py

@@ -4,6 +4,7 @@
 
 import numpy as np
 
+from astropy.coordinates import SkyCoord
 from astropy.io import fits
 from astropy.nddata import CCDData, NDData
 from astropy.table import Table, vstack