This PR adds a type_dict entry for SimpleBlobDetector::blobColor to gen_dict.json, enabling the blobColor property to be exposed in the Java bindings.

As a result, the Java wrapper will automatically generate get_blobColor() and set_blobColor() methods, allowing access to the blobColor field from Java.

Pull Request Readiness Checklist

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

• I agree to contribute to the project under Apache 2 License.
• 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
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake