gaussianBlurAsync error when using kSize values other than (7, 7)

[Correct-Syntax]

Describe the bug

Using values other than (7, 7) for the kSize in the gaussianBlurAsync method results in a crash.

To Reproduce
Steps to reproduce the behavior:

1. Use the code from https://github.com/rainyl/opencv_dart/blob/main/packages/opencv_core/example/lib/main.dart as your project.
2. Change blur = await cv.gaussianBlurAsync(im, (7, 7), 2, sigmaY: 2); to blur = await cv.gaussianBlurAsync(im, (8, 8), 2, sigmaY: 2);
3. When you select an image with the "Pick Image" button, it results in an error/crash.

If I set the kSize back to (7, 7) it works, but any other value doesn't.

Expected behavior
The blur method should not crash with values other than (7, 7).

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop:

• OS: Windows 10

Additional context

The error:

Exception has occurred.
CvException (CvException(code: -215, msg:OpenCV(4.10.0) D:\a\opencv.full\opencv.full\opencv\modules\imgproc\src\smooth.dispatch.cpp:294: error: (-215:Assertion failed) ksize.width > 0 && ksize.width % 2 == 1 && ksize.height > 0 && ksize.height % 2 == 1 in function 'cv::createGaussianKernels'
) in cv::createGaussianKernels of file D:\a\opencv.full\opencv.full\opencv\modules\imgproc\src\smooth.dispatch.cpp:294)

Maybe this is related to #180?

[rainyl]

@Correct-Syntax Have you tried other odd values like (9, 9), (11, 9), (15, 15)? Please note that the kernel size of gaussianBlur must be ODD, refer to https://docs.opencv.org/4.x/d4/d86/group__imgproc__filter.html#gae8bdcd9154ed5ca3cbc1766d960f45c1

[Correct-Syntax]

@rainyl Ah, I see. I'm used to the Python version of OpenCV where they evidently silently correct the values, not matter what is specified. Thank you.