Added button cleanup.

Author: boehlerlukas

src/Gleap.js

@@ -295,7 +295,7 @@ class Gleap {
     GleapReplayRecorder.getInstance().stop();
     GleapStreamedEvent.getInstance().stop();
     GleapFrameManager.getInstance().destroy();
-    GleapFeedbackButtonManager.getInstance().toggleFeedbackButton(false);
+    GleapFeedbackButtonManager.getInstance().destroy();
     GleapNotificationManager.getInstance().clearAllNotifications(true);
     GleapSession.getInstance().clearSession(0, false);
     GleapBannerManager.getInstance().removeBannerUI();

src/GleapFeedbackButtonManager.js

@@ -30,6 +30,18 @@ export default class GleapFeedbackButtonManager {
     return this.instance;
   }
 
+  destroy() {
+    if (this.feedbackButton) {
+      this.feedbackButton.remove();
+      this.feedbackButton = null;
+    }
+
+    this.buttonHidden = null;
+    this.lastButtonIcon = null;
+    this.injectedFeedbackButton = false;
+    this.instance = null;
+  }
+
   /**
    * Toggles the feedback button visibility.
    * @param {*} show