[Email Security] Mention MS Graph API step (#22088)

Author: Maddy-Cloudflare

src/content/docs/cloudflare-one/email-security/setup/post-delivery-deployment/api/office365-api.mdx

@@ -21,6 +21,7 @@ To enable Email Security:
 1. Log in to [Zero Trust](https://one.dash.cloudflare.com/).
 2. Select **Email Security**.
 3. Select **Monitoring**. If you are a first time user, select **Contact sales**. Otherwise, select **Connect an integration**.
+4. Go to **MS Graph API** and select **Authorize**.
 
 Continue with [Enable Microsoft integration](/cloudflare-one/email-security/setup/post-delivery-deployment/api/office365-api/#enable-microsoft-integration) for the next steps.