📝 Add env WHATSAPP_CLOUD_API_URL to possible change https://gr… (#1170)

refs #1117 

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Refactor**
- Dynamically construct API URLs for WhatsApp features using environment
variables for improved reliability and configurability.
- Updated `sendWhatsAppMessage` function to use
`env.WHATSAPP_CLOUD_API_URL` for URL construction, allowing for more
dynamic configuration.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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Co-authored-by: Baptiste Arnaud <baptiste.arnaud95@gmail.com>

packages/env/env.ts

@@ -283,6 +283,11 @@ const whatsAppEnv = {
     WHATSAPP_PREVIEW_FROM_PHONE_NUMBER_ID: z.string().min(1).optional(),
     WHATSAPP_PREVIEW_TEMPLATE_NAME: z.string().min(1).optional(),
     WHATSAPP_PREVIEW_TEMPLATE_LANG: z.string().min(1).optional().default('en'),
+    WHATSAPP_CLOUD_API_URL: z
+      .string()
+      .url()
+      .optional()
+      .default('https://graph.facebook.com'),
   },
 }