fix: Fix issue on failing create action (#622)

This fixes the issue when sometimes the server returns `'Message: Failed
to complete #create action: [undefined method include? for
nil:NilClass in the specified region us-east-1. Please check this AMI is
available in this region.]`

This issue was introduced from
[here](v3.17.0...v3.17.1#diff-5f36235c5a4a35dba130d480e2175640f7762d7ae859ad98efa704c4db646b4fR567)

Co-authored-by: Pelingan, Theodoro <tpelingan@bethel.jw.org>

Author: shierro

lib/kitchen/driver/ec2.rb

@@ -586,7 +586,7 @@ def wait_until_ready(server, state)
               # supplied, try to fetch it from the AWS instance
               fetch_windows_admin_password(server, state)
             else
-              output = server.console_output.output
+              output = server.console_output.output || ''
               unless output.nil?
                 output = Base64.decode64(output)
                 debug "Console output: --- \n#{output}"