fix(whatsapp): Improve WhatsApp webhook payload phone number ID extraction

- Update phone number ID extraction logic for WhatsApp webhook payloads
- Add fallback extraction method using remoteJid when remoteJidAlt is not available
- Ensure consistent phone number ID extraction across different webhook scenarios
- Prevent potential null or incomplete phone number ID assignments

Author: arthurbrenno

agentle/agents/whatsapp/models/whatsapp_webhook_payload.py

@@ -83,4 +83,6 @@ def model_post_init(self, context: Any, /) -> None:
 
         key = self.data.key
         if "@lid" in key.remoteJid:
-            self.phone_number_id = key.remoteJidAlt.split('@')[0]
+            self.phone_number_id = key.remoteJidAlt.split("@")[0]
+
+        self.phone_number_id = key.remoteJid.split("@")[0]