Merge pull request #12503 from nikhedonia:12500-move-gcgraph

* feat: move gcgraph to detail

* chore: puts gcgraph cv::detail namespace

modules/stitching/src/precomp.hpp

@@ -91,8 +91,6 @@
 #  include "opencv2/xfeatures2d/cuda.hpp"
 #endif
 
-#include "../../imgproc/src/gcgraph.hpp"
-
 #include "opencv2/core/private.hpp"
 
 #include "util_log.hpp"

modules/stitching/src/seam_finders.cpp

@@ -41,6 +41,7 @@
 //M*/
 
 #include "precomp.hpp"
+#include "opencv2/imgproc/detail/gcgraph.hpp"
 #include <map>
 
 namespace cv {