[Subscription basic] [zeek] Failing test daily: system test: logs in zeek.http

- Stack version: Same as in Pull Request builds
- Subscription: basic
- Package: zeek
- Failing test: system test: logs
- DataStream: http
- Owners:
- @elastic/integration-experience

Error:
```
could not assign policy to agent: error occurred while waiting for the policy to be assigned to all agents: can't get the agent: could not list agents: could not send request to Kibana API: Get "https://127.0.0.1:5601/api/fleet/agents/7fdaa245-0b43-47d7-bcba-e912907f841f": context deadline exceeded
```

First build failed: https://buildkite.com/elastic/integrations/builds/44707

Latest failed builds:
- https://buildkite.com/elastic/integrations/builds/45020

Start with the failing system test for the zeek.http logs DataStream and compare the referenced Buildkite builds 44707 and 45020. Investigate the policy-assignment timeout while requesting the Kibana API; done means the test completes successfully without the agent-listing timeout.

Written by the indexing model from the issue text.