Videos: Fix audio tracks language.

Video will only return the default language. The rest of the audio
tracks are deleted since they will not be used.

src/invidious/routes/api/manifest.cr

@@ -55,6 +55,10 @@ module Invidious::Routes::API::Manifest
       end
     end
 
+    audio_streams.reject! do |z|
+      z if z.dig?("audioTrack", "audioIsDefault") == false
+    end
+
     manifest = XML.build(indent: "  ", encoding: "UTF-8") do |xml|
       xml.element("MPD", "xmlns": "urn:mpeg:dash:schema:mpd:2011",
         "profiles": "urn:mpeg:dash:profile:full:2011", minBufferTime: "PT1.5S", type: "static",

src/invidious/routes/watch.cr

@@ -152,6 +152,10 @@ module Invidious::Routes::Watch
       end
     end
 
+    audio_streams.reject! do |z|
+      z if z.dig?("audioTrack", "audioIsDefault") == false
+    end
+
     # Older videos may not have audio sources available.
     # We redirect here so they're not unplayable
     if audio_streams.empty? && !video.live_now