Remove empty Additional Resources and Exercises fields from tutorials #26002
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- [x] I agree to contribute to the project under Apache 2 License.
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Patch to opencv_extra has the same branch name.
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This PR is in response to issue [26001](https://github.com/opencv/opencv/issues/26001)
This pull request addresses the issue of empty "Additional Resources" and "Exercises" fields in several OpenCV-Python tutorials. The empty sections have been removed to improve the clarity and consistency of the documentation.
Add initialisations to make clear what values actually have to be passed.
Moreover, in accordance with 383559c228/modules/flann/include/opencv2/flann/defines.h (L68), I believe `FLANN_INDEX_KDTREE` was being initialised wrongly in the code examples, 1 should be correct, whereas 0 is `FLANN_INDEX_LINEAR`.