Make sure the found chunk stays loaded

This is done by adding a plugin chunk ticket and removing it once our logic is done

randomteleport-plugin/src/main/java/de/themoep/randomteleport/searcher/RandomSearcher.java

@@ -455,6 +455,8 @@ public class RandomSearcher {
                 checkRandom(future);
                 return false;
             }
+            c.addPluginChunkTicket(plugin);
+            try {
                 int indexOffset = random.nextInt(RANDOM_LIST.size());
                 Location foundLoc = null;
                 for (int i = 0; i < RANDOM_LIST.size(); i++) {
@@ -490,6 +492,9 @@ public class RandomSearcher {
                     checkRandom(future);
                 }
                 return false;
+            } finally {
+                c.removePluginChunkTicket(plugin);
+            }
         }).exceptionally(future::completeExceptionally);
     }