Updated test type hint

[radarhere]

Minor type hint update. In the following fixture, the return type can be the more specific ImageFile, rather than just Image. The current version was written before #7944 updated the return type of Image.open to ImageFile.

Pillow/Tests/test_image_resize.py

Lines 181 to 188 in d59b169

	@pytest.fixture
	def gradients_image() -> Generator[Image.Image, None, None]:
	with Image.open("Tests/images/radial_gradients.png") as im:
	im.load()
	try:
	yield im
	finally:
	im.close()