PngImageFile text is a property

[radarhere]

This is part of #8362 - I'm hoping to break down that PR into easier-to-review chunks.

Pillow/Tests/test_file_png.py

Lines 617 to 621 in aa0f412

	# Raises a UnicodeDecodeError in load_end
	with Image.open("Tests/images/truncated_image.png") as im:
	# The file is truncated
	with pytest.raises(OSError):
	im.text()

is testing

Pillow/src/PIL/PngImagePlugin.py

Lines 821 to 822 in aa0f412

	@property
	def text(self) -> dict[str, str | iTXt]:

Since this is a @property, it can be accessed with just im.text