Merge pull request #27977 from asmorkalov:as/proper_ffmpeg_diagnostic_windows_arm

Fixed pre-built ffmpeg diagnostics on Windows for ARM. #27977

### 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
- [ ] 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

CMakeLists.txt

@@ -1627,7 +1627,7 @@ endif()
 if(WITH_FFMPEG OR HAVE_FFMPEG)
   if(OPENCV_FFMPEG_USE_FIND_PACKAGE)
     status("    FFMPEG:"       HAVE_FFMPEG         THEN "YES (find_package)"                       ELSE "NO (find_package)")
-  elseif(WIN32)
+  elseif(WIN32 AND NOT ARM AND NOT AARCH64)
     status("    FFMPEG:"       HAVE_FFMPEG         THEN "YES (prebuilt binaries)"                  ELSE NO)
   else()
     status("    FFMPEG:"       HAVE_FFMPEG         THEN YES ELSE NO)

modules/videoio/cmake/detect_ffmpeg.cmake

@@ -12,7 +12,7 @@ if(NOT HAVE_FFMPEG AND OPENCV_FFMPEG_USE_FIND_PACKAGE)
   endif()
 endif()
 
-if(NOT HAVE_FFMPEG AND WIN32 AND NOT ARM AND NOT OPENCV_FFMPEG_SKIP_DOWNLOAD)
+if(NOT HAVE_FFMPEG AND WIN32 AND NOT ARM AND NOT AARCH64 AND NOT OPENCV_FFMPEG_SKIP_DOWNLOAD)
   include("${OpenCV_SOURCE_DIR}/3rdparty/ffmpeg/ffmpeg.cmake")
   download_win_ffmpeg(FFMPEG_CMAKE_SCRIPT)
   if(FFMPEG_CMAKE_SCRIPT)