add specific error code when cvtColor is used on an image with an invalid number of channels #25971
Description
Describe the feature and motivation
When I (on accident) use cvtColor twice to convert a grayscale image to RGB than at the moment only a generic error code (-2 / cv.Error.StsError) is raised. Could we instead use a more specific error code like e.g. (cv.Error.BadNumChannels/ -15).
Additional context
No response