feat: Updated code to get english transcript from filename

xmodule/video_block/transcripts_utils.py

@@ -1021,6 +1021,26 @@ def get_transcript_from_contentstore(video, language, output_format, transcripts
         except (KeyError, NotFoundError):
             continue
 
+    if transcript_content is None and language == 'en':
+        # `get_transcript_for_video`` can get the transcript using just the filename,
+        # but in the above loop the filename from 'en' is overwritten.
+        #
+        # If it doesn't yet have the transcription and the language is 'en',
+        # check again but this time using the original filename.
+        #
+        # The use case for which this has been implemented is when copying a video from
+        # a library and pasting it into a course.
+        # The asset is copied, but we only have the filename to obtain the content.
+        try:
+            input_format, base_name, transcript_content = get_transcript_for_video(
+                video.location,
+                subs_id=sub_id,
+                file_name=other_languages['en'],
+                language=language
+            )
+        except (KeyError, NotFoundError):
+            pass
+
     if transcript_content is None:
         raise NotFoundError('No transcript for `{lang}` language'.format(
             lang=language