Return distinct extension array

Diligent.WebAPI.Business/Services/TagService.cs

             using var connection = new SqlConnection(_configuration.GetConnectionString("WebApi"));
             var files = await connection.QueryAsync<FileFilterReturnDto>("SELECT * FROM Files  inner join DocumentOrganizerDocStore on DocumentOrganizerDocStore.stream_id = Files.DocumentId;");
 
-            var extensionsArray = files.Select(x => x.file_type).ToArray();
+            var extensionsArray = files.Select(x => x.file_type).Distinct().ToArray();
 
             return new FileFiltersReturnDTO
             {