Fix warnings part 8 (#8113)

* Fix CA1819 and CA1002 warnings

Changed the type of Languages statistic in regression tests from
Language[] to List<Language>. By doing that, the warning CA1819 was
removed but then the warning CA1002 was raised. However, this warning
was expected to be excluded from QuantConnect.Algorithm.CSharp.

* Improve implementation

* Simplify code

* Fix bugs

Algorithm.CSharp/CustomDataUsingMapFileRegressionAlgorithm.cs

@@ -114,7 +114,7 @@ namespace QuantConnect.Algorithm.CSharp
         /// <summary>
         /// This is used by the regression test system to indicate which languages this algorithm is written in.
         /// </summary>
-        public Language[] Languages { get; } = { Language.CSharp, Language.Python };
+        public List<Language> Languages { get; } = new() { Language.CSharp, Language.Python };
 
         /// <summary>
         /// Data Points count of all timeslices of algorithm