Translate the ISO-639-2/B codes to ISO-639-2/T. (#13068)

* Translate the ISO-639-2/B codes to ISO-639-2/T.

This enables 19 additional languages to be displayed correctly.

* Convert the 2-dimensional array to a dictionary

* Added the French language to the list of ISO-639-2/B codes

* Don't change the property, use a local variable instead.

* When creating the MediaStream in the MediaStreamRepository ensure that the ISO 639-2/T (f.e. deu) code is used for the language as that is the one the .NET culture info knows.
The other code is most likely the ISO 639-2/B code (f.e. ger) which is unknown to the .NET culture info and will result in just displaying the code instead of the display name.

* Move the substitution of ISO 639-2/B to /T to the localization manager.
Some language (like Chinese) have multiple entries in the iso6392.txt file (f.e. zho|chi|zh|..., zho|chi|zh-tw|...) but the conversation between /T and /B is the same so use .TryAdd.

* Change the method definition from GetISO6392TFromB to TryGetISO6392TFromB and return true if a case was found.

* Add unit tests for TryGetISO6392TFromB.

Jellyfin.Server.Implementations/Item/MediaStreamRepository.cs

@@ -100,7 +100,18 @@ public class MediaStreamRepository : IMediaStreamRepository
 
         dto.IsAVC = entity.IsAvc;
         dto.Codec = entity.Codec;
-        dto.Language = entity.Language;
+
+        var language = entity.Language;
+
+        // Check if the language has multiple three letter ISO codes
+        // if yes choose the first as that is the ISO 639-2/T code we're needing
+        if (language != null && _localization.TryGetISO6392TFromB(language, out string? isoT))
+        {
+            language = isoT;
+        }
+
+        dto.Language = language;
+
         dto.ChannelLayout = entity.ChannelLayout;
         dto.Profile = entity.Profile;
         dto.AspectRatio = entity.AspectRatio;