[dotnet] Encoding process output

Fixes #11947

Author: diemol

dotnet/src/webdriver/SeleniumManager.cs

@@ -145,6 +145,8 @@ private static string RunCommand(string fileName, string arguments)
             process.StartInfo.FileName = $"{basePath}/{fileName}";
             process.StartInfo.Arguments = arguments;
             process.StartInfo.UseShellExecute = false;
+            process.StartInfo.StandardErrorEncoding = Encoding.UTF8;
+            process.StartInfo.StandardOutputEncoding = Encoding.UTF8;
             process.StartInfo.RedirectStandardOutput = true;
             process.StartInfo.RedirectStandardError = true;