Replace usages of Guava EventBus with custom one

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

runelite-client/src/main/java/net/runelite/client/util/DeferredEventBus.java

@@ -24,11 +24,11 @@
  */
 package net.runelite.client.util;
 
-import com.google.common.eventbus.EventBus;
 import java.util.Queue;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import javax.inject.Inject;
 import javax.inject.Singleton;
+import net.runelite.api.events.EventBus;
 
 @Singleton
 public class DeferredEventBus extends EventBus