Wait for big subtitles to render.

cms/djangoapps/contentstore/features/video-editor.feature

@@ -59,6 +59,7 @@ Feature: CMS Video Component Editor
     And I open tab "Advanced"
     And I upload transcript file "1mb_transcripts.srt" for "uk" language code
     And I save changes
+    And I wait for "10" seconds
     Then when I view the video it does show the captions
     And I see "Привіт, edX вітає вас." text in the captions