Validate size and rank when initializing RankFilter

[radarhere]

from PIL import Image, ImageFilter
im = Image.new("L", (100, 100))
rankfilter = ImageFilter.RankFilter(2, 1)
im.filter(rankfilter)

gives

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "PIL/Image.py", line 1463, in filter
    return self._new(filter.filter(self.im))
                     ^^^^^^^^^^^^^^^^^^^^^^
  File "PIL/ImageFilter.py", line 110, in filter
    return image.rankfilter(self.size, self.rank)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ValueError: bad filter size

See

Pillow/src/PIL/ImageFilter.py

Line 101 in 9c1097c

def __init__(self, size: int, rank: int) -> None:

Pillow/src/libImaging/RankFilter.c

Lines 71 to 73 in 9c1097c

	if (!(size & 1)) {
	return (Imaging)ImagingError_ValueError("bad filter size");
	}

The size value used when constructing RankFilter was incorrect. However, it's only purpose is to be used as a filter.

So let's raise the error on construction, rather than letting the user think everything is ok at first.

This also applies to

Pillow/src/libImaging/RankFilter.c

Lines 83 to 85 in 9c1097c

	if (rank < 0 || rank >= size2) {
	return (Imaging)ImagingError_ValueError("bad rank value");
	}

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