Handle errors during execution as info messages instead of exceptions (#596)

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/Query.cs

@@ -379,6 +379,7 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
                 if (sqlConn != null)
                 {
                     // Subscribe to database informational messages
+                    sqlConn.GetUnderlyingConnection().FireInfoMessageEventOnUserErrors = true;
                     sqlConn.GetUnderlyingConnection().InfoMessage += OnInfoMessage;
                 }