[dotnet] Capture error output from selenium manager (#11320)

* Capture error output from selenium manager

* Revert DriverService back to hide exceptions

Author: nvborisenko

dotnet/src/webdriver/SeleniumManager.cs

@@ -24,6 +24,8 @@
 using System.Runtime.InteropServices;
 #endif
 
+using System.Text;
+
 namespace OpenQA.Selenium
 {
     /// <summary>
@@ -112,22 +114,38 @@ private static string RunCommand(string fileName, string arguments)
             process.StartInfo.Arguments = arguments;
             process.StartInfo.UseShellExecute = false;
             process.StartInfo.RedirectStandardOutput = true;
+            process.StartInfo.RedirectStandardError = true;
 
-            string output;
+            StringBuilder outputBuilder = new StringBuilder();
+            
+            DataReceivedEventHandler outputHandler = (sender, e) => outputBuilder.AppendLine(e.Data);
 
             try
             {
+                process.OutputDataReceived += outputHandler;
+                process.ErrorDataReceived += outputHandler;
+                
                 process.Start();
-                output = process.StandardOutput.ReadToEnd();
+
+                process.BeginOutputReadLine();
+                process.BeginErrorReadLine();
+
                 process.WaitForExit();
             }
             catch (Exception ex)
             {
                 throw new WebDriverException($"Error starting process: {fileName} {arguments}", ex);
             }
+            finally
+            {
+                process.OutputDataReceived -= outputHandler;
+                process.ErrorDataReceived -= outputHandler;
+            }
+
+            string output = outputBuilder.ToString();
 
             if (!output.StartsWith("INFO")) {
-                throw new WebDriverException($"Invalid response from process: {fileName} {arguments}");
+                throw new WebDriverException($"Invalid response from process: {fileName} {arguments}\n{output}");
             }
 
             return output;