Merge pull request #26211 from Kumataro:fix26207

imgcodecs: implement imencodemulti() #26211

Close #26207
### 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
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/imgcodecs/test/test_avif.cpp

@@ -161,14 +161,14 @@ TEST_P(Imgcodecs_Avif_Image_EncodeDecodeSuite, imencode_imdecode) {
 
   // Encode.
   std::vector<unsigned char> buf;
-  if (!IsBitDepthValid()) {
-    EXPECT_THROW(cv::imencode(".avif", img_original, buf, encoding_params_),
-                 cv::Exception);
-    return;
-  }
   bool result = true;
   EXPECT_NO_THROW(
       result = cv::imencode(".avif", img_original, buf, encoding_params_););
+
+  if (!IsBitDepthValid()) {
+    EXPECT_FALSE(result);
+    return;
+  }
   EXPECT_TRUE(result);
 
   // Read back.