feat: forward the subscribers abort signal in event listener

spec.bs

@@ -1811,11 +1811,12 @@ partial interface EventTarget {
                :: false
 
                : [=event listener/signal=]
-               :: null
+               :: |subscriber|'s [=Subscriber/subscription controller=]'s [=AbortController/signal=]
 
-                  Note: The {{AbortSignal}} for event listeners [=add an event listener|added=] by
-                  {{EventTarget/when()}} is managed by the {{Observable}} itself. See
-                  {{Observable/subscribe()}} and {{SubscribeOptions}}.
+                  Note: To ensure that the [=event listener=] is cleaned up when
+                  [=Subscriber/subscription controller=]'s [=AbortController/signal=] is [=AbortSignal/aborted=].
+                  Preventing listener leaks regardless of whether {{Observable}} or {{EventTarget}} depending on
+                  ownership model in engines.
 
     1. Return |observable|.
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