Fix a bug in starting up the server with unknown role types

Author: shs96c

java/server/src/org/openqa/grid/selenium/GridLauncherV3.java

@@ -115,7 +115,7 @@ private static GridItemLauncher buildLauncher(String[] args) {
       return null;
     }
 
-    Supplier<GridItemLauncher> supplier = LAUNCHERS.get(gridRole);
+    Supplier<GridItemLauncher> supplier = LAUNCHERS.get(gridRole.toString());
     if (supplier == null) {
       System.err.println("Unknown role: " + gridRole);
       return null;