Fix TMDB import failing when no IMDB ID is set for a movie (#12891)

CONTRIBUTORS.md

@@ -192,6 +192,7 @@
  - [jaina heartles](https://github.com/heartles)
  - [oxixes](https://github.com/oxixes)
  - [elfalem](https://github.com/elfalem)
+ - [benedikt257](https://github.com/benedikt257)
 
 # Emby Contributors
 

MediaBrowser.Providers/Plugins/Tmdb/Movies/TmdbMovieProvider.cs

@@ -198,7 +198,7 @@ namespace MediaBrowser.Providers.Plugins.Tmdb.Movies
             };
 
             movie.SetProviderId(MetadataProvider.Tmdb, tmdbId);
-            movie.SetProviderId(MetadataProvider.Imdb, movieResult.ImdbId);
+            movie.TrySetProviderId(MetadataProvider.Imdb, movieResult.ImdbId);
             if (movieResult.BelongsToCollection is not null)
             {
                 movie.SetProviderId(MetadataProvider.TmdbCollection, movieResult.BelongsToCollection.Id.ToString(CultureInfo.InvariantCulture));