[Engine] DocGen jobs not being processed for new enterprise customers

Title: For new Xray Enterprise installations, jobs are unable to be processed and get stuck at 8%

Short description:

While setting up staging-0 EU env, we noticed that the jobs were not being processed after everything was correctly deployed. With further investigation we could see the following errors on the import task:

For this particular tenant, we only have the Xray tenant entry on addOnSettingsEnterprise collection and not on addOnSettings (standard).
Tested adding a manual entry on addOnSettings (standard) and it solved the issue, hence concluding this is a bug introduced by the standalone apps changes. 

Steps to reproduce:

1. Create a new Jira Cloud instance
2. Install Xray enterprise
3. Use the "Get Started" page to create the Demo Project
4. Access a test or other Xray issue details page
5. Try to export data using DocGen

Actual result: The DocGen exports are not being processed and get stuck at 8%.

Expected result: DocGen exports should work as expected.

Video Evidence:
Screen Recording 2025-10-09 at 15.17.09.mov

^{This is also the same as: https://jira.getxray.app/browse/XPORTERCLOUD-2453}