[Website] Clarify Watcher reporting limitations on Elastic Cloud

### Type of issue

Inaccurate

### What documentation page is affected

https://www.elastic.co/docs/deploy-manage/deploy/elastic-cloud/restrictions-known-problems

### What happened?

I think this section could be reworded as it can be confusing and get incorrectly overlooked.
1. The limitation applies to all report types, not only PDF reports. (The same `additional_token_enabled` workaround is needed for CSV reports, for instance)
2. Kibana Reporting in Watcher uses the `email` action with report attachments, not a Watcher webhook.
3. The phrase “bypass network security” might be unclear to users who do not yet associate "network security" with Elastic Cloud "traffic filters".

Current:

>## PDF report generation using Alerts or Watcher webhooks
>
>- PDF report automatic generation via Alerts is not possible on Elastic Cloud.
>- PDF report generation isn’t possible for deployments running on Elastic Stack version 8.7.0 or before that are protected by network security. This limitation doesn’t apply to public webhooks such as Slack, PagerDuty, and email. For deployments running on Elastic Stack version 8.7.1 and beyond, [PDF report automatic generation via Watcher webhook](/docs/explore-analyze/report-and-share/automating-report-generation#use-watcher) is possible using the `xpack.notification.webhook.additional_token_enabled` configuration setting to bypass network security.

Proposing:

>## Report generation using Alerts or Watcher
>
>- Automatic report generation via Alerts is not possible on Elastic Cloud.
>- Automatic report generation is not possible for deployments running on Elastic Stack version 8.7.0 or earlier that are protected by network security (formerly traffic filters). This applies to all report types (PDF, CSV, and PNG). This limitation doesn’t apply to public webhooks such as Slack, PagerDuty, and email.
>- For deployments running on Elastic Stack version 8.7.1 and later, [automatic report generation using Watcher email actions with report attachments](/docs/explore-analyze/report-and-share/automating-report-generation#use-watcher) is possible when the `xpack.notification.webhook.additional_token_enabled` configuration setting is enabled. This setting allows the reporting job to access Kibana when network security is enabled.

### Additional info

_No response_