Added OnnxRuntime GPU wrapper #28588
### Pull Request Readiness Checklist
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- [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
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- [x] There is a reference to the original bug report and related work
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Patch to opencv_extra has the same branch name.
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samples: add compatibility note for Mask R-CNN in OpenCV 5.0 #28053
### Pull Request Readiness Checklist
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
- [ ] 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
### Summary
Updates documentation in `samples/dnn/mask_rcnn.py` to clarify a compatibility issue with OpenCV 5.0.
### Details
As verified in issue #27240, OpenCV 5.0 introduces stricter graph optimization. The default `.pbtxt` used in this sample treats `detection_out_final` as an intermediate layer (it is not listed in `getUnconnectedOutLayersNames`).
While OpenCV 4.x implicitly allows retrieving this layer, OpenCV 5.0 throws an error when requesting it:
> "the number of requested and actual outputs must be the same"
This PR adds:
1. A warning note in the file header explaining the strict output requirement.
2. An inline comment near `net.forward()` to guide users debugging this error.
Relates to issue: #27240
Abhishek Gola
TonyCY24
Ningxin Hu
Alexander Alekhin
Dmitry Kurtaev