ConversionContext.getContentTree returns one page when --data-version is included

Issue Summary

When using ConversionContext.getContentTree API to get all pages in a tree it returns 1 or current page for Confluence server 6.12.1 but returns all for 6.11.0 but only with --data-version argument on ASDK debug.

Steps to Reproduce

1. Download sample app: conf-transformer-test.zip
2. Run "atlas-clean && atlas-run -v 6.12.0 --data-version 6.12.0" in conf-transformer-test folder
3. In Demonstration space:
4. Go to Space tools -> Content tools -> Export
5. Select PDF
6. Select type (I've tried both Normal and Custom)
7. Notice "Found 1 pages" in log and debugger for each page in PDF
8. Create DEV space with 4 pages (3 siblings and 1 child page)
9. Follow the same steps as for DS and get the same result

Expected Results

ConversionContext.getContentTree returns a object containing all pages to be included in export

Actual Results

ConversionContext.getContentTree returns an object containing only current page

Notes

• API returns expected number of pages when command is atlas-clean && atlas-debug -version 6.11.0 or 6.12.0
• From server ecosystem team: "--data-version should match --version unless one might want to test for an upgrade path from an older database version. In some cases not setting --data-version and setting --version can have undesired results because it may try and set --data-version to latest and that could be a cloud version though it's unlikely"

Impact

• From vendor:

  My add-ons provide special behavior when multiple pages are exported in one PDF. Unfortunately this is no longer possible in Confluence 6.13 because of ConversionContext.getContentTree now only returns the current page, not the list of all pages included in the PDF. There doesn't appear to be any other way to get this information.

  This change means that my users will lose a useful feature.

• Vendor has 1.5k customer installs potentially affected by this
• This has not been tested on prod instance

Workaround

Use atlas-clean && atlas-debug -version 6.11.0 or 6.12.0 when debugging