Windows agent is not available on Fleet UI on restart when installed with `--delay-enroll` and `--unprivileged`.

[amolnater-qasource]

Kibana Build details:

VERSION: 8.14.0 BC3
BUILD: 73762
COMMIT: 2a492e1625f24336f3259b2b8df62b2b18127e81

Artifact Link: https://staging.elastic.co/8.14.0-7c638435/downloads/beats/elastic-agent/elastic-agent-8.14.0-windows-x86_64.zip

Preconditions:

1. 8.14.0-BC3 Kibana cloud environment should be available.

Steps to reproduce:

1. Run agent install command with --delay-enroll and --unprivileged.
2. Observe agent is successfully installed.
3. Restart the Windows host.
4. Observe agent is not visible on Fleet UI and the Elastic Agent service is not started.

Note:
Issue is consistently reproducible on multiple Windows Hosts.

Expected Result:
Windows agent should be available on Fleet UI on restart when installed with --delay-enroll and --unprivileged.

Logs:
logs.zip
logs2.zip

Screenshot:

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[amolnater-qasource]

@manishgupta-qasource Please review.

[manishgupta-qasource]

Secondary review for this ticket is Done

[cmacknz]

{"log.level":"info","@timestamp":"2024-05-06T07:27:41.736Z","log.origin":{"file.name":"cmd/run.go","file.line":180},"message":"Elastic Agent started","log":{"source":"elastic-agent"},"process.pid":3400,"agent.version":"8.14.0","agent.unprivileged":true,"ecs.version":"1.6.0"}
{"log.level":"error","@timestamp":"2024-05-06T07:27:41.771Z","log.origin":{"file.name":"cmd/run.go","file.line":147},"message":"failed to perform delayed enrollment: could not create new vault: The operation completed successfully.","log":{"source":"elastic-agent"},"ecs.version":"1.6.0"}

[amolnater-qasource]

Hi Team,
We have revalidated this issue on latest 8.17.0 BC5 kibana cloud environment and found it fixed now.

Observations:

• Windows agent should be available on Fleet UI on restart when installed with --delay-enroll and --unprivileged.

Screenshots:

Build details:
VERSION: 8.17.0 BC5
BUILD: 80495
COMMIT: 5c78fb5e4e9b5063bd83ae9bd1e5b32c63f5cc34
Artifact Link: https://staging.elastic.co/8.17.0-a18e6540/downloads/beats/elastic-agent/elastic-agent-8.17.0-windows-x86_64.zip

Hence we are marking this issue as QA:Validated.

Thanks!