feat(airship): Added new method waitForChannelId()

src/@awesome-cordova-plugins/plugins/airship/index.ts

@@ -1664,6 +1664,16 @@ class AirshipChannel {
     return;
   }
 
+  /**
+   * Waits for the channel ID to be created
+   * Returns the channel ID. If the channel ID is not yet created the function it will wait for it before returning.
+   * After the channel ID is created, this method functions the same as getChannelId().
+   */
+  @CordovaInstance()
+  waitForChannelId(): Promise<string> {
+    return;
+  }
+
   /**
    * Gets a list of the channel's subscriptions.
    */