Remove ComposableController generic type parameters

These generic type parameters weren't really used in practice. They
were passed to the `messagingSystem`, but we erased the type of the
messaging system in the one place that we call it, making the more
specific types pointless. You can tell that they weren't useful because
they were never set in tests, and everything still worked.

src/ComposableController.ts

@@ -1,8 +1,5 @@
 import BaseController from './BaseController';
-import {
-  RestrictedControllerMessenger,
-  EventConstraint,
-} from './ControllerMessenger';
+import { RestrictedControllerMessenger } from './ControllerMessenger';
 
 /**
  * List of child controller instances
@@ -21,18 +18,15 @@ export type ControllerList = (
 /**
  * Controller that can be used to compose multiple controllers together
  */
-export class ComposableController<
-  Events extends EventConstraint,
-  AllowedEvents extends string
-> extends BaseController<never, any> {
+export class ComposableController extends BaseController<never, any> {
   private controllers: ControllerList = [];
 
   private messagingSystem?: RestrictedControllerMessenger<
     'ComposableController',
     never,
-    Events,
+    any,
     never,
-    AllowedEvents
+    any
   >;
 
   /**
@@ -51,9 +45,9 @@ export class ComposableController<
     messenger?: RestrictedControllerMessenger<
       'ComposableController',
       never,
-      Events,
+      any,
       never,
-      AllowedEvents
+      any
     >,
   ) {
     super(

src/ControllerMessenger.ts

@@ -24,14 +24,7 @@ type ExtractEventPayload<Event, T> = Event extends { type: T; payload: infer P }
   : never;
 
 type ActionConstraint = { type: string; handler: (...args: any) => unknown };
-
-/**
- * A valid ControllerMessenger Event.
- *
- * This type is used to constrain generic Event parameters, to ensure valid
- * Event types are given.
- */
-export type EventConstraint = { type: string; payload: unknown[] };
+type EventConstraint = { type: string; payload: unknown[] };
 
 /**
  * A namespaced string