Null-check location for multi-location clues

Sometimes it can be null.

Signed-off-by: Tomas Slusny <slusnucky@gmail.com>

runelite-client/src/main/java/net/runelite/client/plugins/cluescrolls/ClueScrollPlugin.java

@@ -308,7 +308,10 @@ public class ClueScrollPlugin extends Plugin
 				{
 					for (WorldPoint location : locations)
 					{
-						highlightObjectsForLocation(location, objectIds);
+						if (location != null)
+						{
+							highlightObjectsForLocation(location, objectIds);
+						}
 					}
 				}
 			}