feat: handle missing QR code

If the QR code is not successfully generated, send the user a notification. A notification is chosen for persistence, otherwise text on the screen may be lost on boot.

Closes #49

ovos_PHAL_plugin_homeassistant/__init__.py

@@ -883,6 +883,9 @@ def handle_qr_oauth_response(self, message):
         @param message: oauth.generate.qr.response
         """
         qr_code_url = message.data.get("qr")
+        if qr_code_url is None:
+            self.gui.show_notification("Failed to get QR code for Home Assistant login!")
+            return
         LOG.info(f"Got qr code: {qr_code_url}")
         self.gui.send_event("ovos.phal.plugin.homeassistant.oauth.qr.update", {
             "qr": qr_code_url