Merge pull request #23691 from dkurt:pycv_float16_fixes

Import and export np.float16 in Python #23691

### Pull Request Readiness Checklist

* Also, fixes `cv::norm` with `NORM_INF` and `CV_16F`

resolves https://github.com/opencv/opencv/issues/23687

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/python/test/test_norm.py

@@ -88,7 +88,7 @@ def get_element_types(norm_type):
         return (np.uint8,)
     else:
         return (np.uint8, np.int8, np.uint16, np.int16, np.int32, np.float32,
-                np.float64)
+                np.float64, np.float16)
 
 
 def generate_vector(shape, dtype):