concord-server: fix ExternalEventTriggerProcessor binding

Author: ibodrov

server/impl/src/main/java/com/walmartlabs/concord/server/events/ExternalEventResource.java

@@ -60,15 +60,15 @@ public class ExternalEventResource implements Resource {
     private final TriggerProcessExecutor executor;
     private final UserManager userManager;
     private final TriggerEventInitiatorResolver initiatorResolver;
-    private final List<ExternalEventTriggerProcessor> processors;
+    private final Set<ExternalEventTriggerProcessor> processors;
     private final AuditLog auditLog;
 
     @Inject
     public ExternalEventResource(ExternalEventsConfiguration cfg,
                                  TriggerProcessExecutor executor,
                                  UserManager userManager,
                                  TriggerEventInitiatorResolver initiatorResolver,
-                                 List<ExternalEventTriggerProcessor> processors,
+                                 Set<ExternalEventTriggerProcessor> processors,
                                  AuditLog auditLog) {
 
         this.cfg = cfg;