ac:custom-content:search-body content property is not indexed

Issue Summary

Users can add the ac:custom-content:search-body content property to custom content in confluence to add searchable text to the custom content. 

Steps to Reproduce

1. Create a custom content such as a draw.io or gliffy diagram
2. Save the diagram and publish the page
3. Search for the diagram by filtering by its type and copy its ID
4. Access

   https://instance.atlassian.net/wiki/rest/api/content/CONTENT_ID/property/ac:custom-content:search-body

1. Perform a new search using the terms returned by that property

Expected Results

The search should return the custom content (in this case the diagram)

Actual Results

Not found

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available