DD link disappears from the build info after restart

[kott-off]

Describe the bug
DataDog link disappears from the build info page after Jenkins restart.

To Reproduce
Steps to reproduce the behavior:

1. Go to Jenkins build page.
2. Click on "Build Now"
3. Wait the build end before "View in Datadog" link appears in left pane.
4. Restart Jenkins
5. Observe the link "View in Datadog" from step 3 has gone.

Expected behavior
The "View in Datadog" link persists after Jenkins restart

Environment and Versions:
datadog plugin: 9.1.6
Jenkins LTS: 2.492.3