[EKS KSPM] Error running fetcher for key process

**Describe the bug**
During a scan cycle in kspm/eks an error occurred:

```
[elastic_agent.cloudbeat][error] Error running fetcher for key process: open /hostfs/proc/27920/stat: no such file or directory
```

This led Cloudbeat to publish fewer events than expected (4 instead of 15).

More detailed logs of that cycle:

The problem was resolved in the subsequent cycle, restoring the previously missed events.

**Preconditions**
It happened to ess live environment with version `v8.12.0`.
Security Posture Management: `v1.7.4`
Elastic agent: `8.12.0`