Provide Overview comments about Raw Data Exports vs Figure exports

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Which topic?

https://developer.adobe.com/commerce/services/reporting/export-api/#raw-data-exports

### What's wrong with the content?

Raw Data exports are only available as zip compressed CSV files, where as Report exports (Figure or Chart) are available as CSV files or direct JSON objects. A few extra lines of explanation would be beneficial on the page to advise the basic outline of operations and to set expectations, as has been included on many other pages in Adobe documentation. Appreciate it might repeat some material already on the page but it helps tie it together and direct the user to the relevant section for their purpose.

### What changes do you propose?

You might update the info box beneath Raw Data Exports to say a little more:
“
Raw Data Exports are zip-compressed CSV file containing the whole raw data of a specified data warehouse table, that can be generated via the Manage Data > Raw Data Exports tool in MBI, or via the [Create a Raw Data Export of a Table](https://developer.adobe.com/commerce/services/reporting/export-api/#create-a-raw-data-export-of-a-table) API call (though note that Raw Data Exports created via API will not be listed in the Raw Data Exports section of MBI, only the export created via the MBI application itself). The Raw Data Export zip file can then be exported via the [Get A Specific Export](https://developer.adobe.com/commerce/services/reporting/export-api/#get-a-specific-export) API call, using the Export ID.

In order to return data directly in JSON format, you can instead stage the required data in a Report, then export the Report data using the Figure ID (or Chart ID for Charts created via the cohort report builder) using the relevant API calls listed below, in which you can specify to export in JSON format.
”

### Anything else that can help to cover this?

_No response_

Open the Reporting Export API page at the Raw Data Exports section and read the existing info box alongside the Create a Raw Data Export of a Table and Get A Specific Export sections. Update the overview to distinguish raw-data ZIP/CSV exports from Figure or Chart exports and explain the relevant MBI, API, and JSON options; the documentation should clearly guide readers to the appropriate API section.

Written by the indexing model from the issue text.