[Website]: Add a note about enabling "Manage Scheduled Reports" in the Space when scheduling reports

### Before you submit

- [x] This issue is about a documentation page, flow, or piece of content.

### Type of issue

Missing information

### What documentation page or section is affected

https://www.elastic.co/docs/explore-analyze/report-and-share/automating-report-generation

### What happened?

When trying to schedule a report from a specific Space, users won’t be able to schedule it if Manage Scheduled Reports isn’t enabled under the Space’s Management group, even if they have all the necessary privileges.

This dependency may not be obvious, as users might not think to check which features are enabled for the Space.

We could add a note reminding users to make sure Manage Scheduled Reports is enabled in the Space.

### Additional info

_No response_

Open the affected page at https://www.elastic.co/docs/explore-analyze/report-and-share/automating-report-generation and find the section describing how to schedule reports. Add a note that Manage Scheduled Reports must be enabled under the Space’s Management group. Done means users scheduling reports from a Space can see this prerequisite.

Written by the indexing model from the issue text.