Remove non-zero token length requirement to allow more flexibility for token providers

Author: alec-petersen

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/TokenProvider`1.mustache

@@ -36,9 +36,6 @@ namespace {{packageName}}
         public TokenProvider(IEnumerable<TTokenBase> tokens)
         {
             _tokens = tokens.ToArray();
-
-            if (_tokens.Length == 0)
-                throw new ArgumentException("You did not provide any tokens.");
         }
     }
 }