Fix nested global action binding

Fixes #307

References:
- https://discourse.stimulusjs.org/t/is-it-intentional-that-parent-controllers-also-listens-to-actions-within-child-controller/1127
- https://codepen.io/javan/pen/JjYMYKO?editors=1010

packages/@stimulus/core/src/binding.ts

@@ -63,7 +63,7 @@ export class Binding {
     } else if (eventTarget instanceof Element && this.element.contains(eventTarget)) {
       return this.scope.containsElement(eventTarget)
     } else {
-      return true
+      return this.scope.containsElement(this.action.element)
     }
   }
 

packages/@stimulus/core/src/tests/cases/action_tests.ts

@@ -6,7 +6,7 @@ export default class ActionTests extends LogControllerTestCase {
     <div data-controller="c" data-action="keydown@window->c#log">
       <button data-action="c#log"><span>Log</span></button>
       <div id="outer" data-action="click->c#log">
-        <div id="inner" data-controller="c" data-action="click->c#log"></div>
+        <div id="inner" data-controller="c" data-action="click->c#log keyup@window->c#log"></div>
       </div>
       <div id="multiple" data-action="click->c#log click->c#log2 mousedown->c#log"></div>
     </div>
@@ -45,6 +45,12 @@ export default class ActionTests extends LogControllerTestCase {
     this.assertActions({ name: "log", eventType: "keydown" })
   }
 
+  async "test nested global actions"() {
+    const innerController = this.controllers[1]
+    await this.triggerEvent("#outside", "keyup")
+    this.assertActions({ controller: innerController, eventType: "keyup" })
+  }
+
   async "test multiple actions"() {
     await this.triggerEvent("#multiple", "mousedown")
     await this.triggerEvent("#multiple", "click")