Docs: host OTel collector config missing mute_process_user_error causes log spam

[mahdi13830510]

Describe the bug
The host OpenTelemetry Collector setup documentation at /docs/telemetry/host-otel-collector includes mute_process_name_error: true under the process scraper but omits mute_process_user_error: true. When the collector runs as a systemd service on a host where /etc/passwd is not accessible (e.g., container hosts, hardened systems), the process scraper floods container logs with:

error reading username for process "<name>" (pid X): open /etc/passwd: no such file or directory

This was reported in the upstream OTel contrib project: open-telemetry/opentelemetry-collector-contrib#48628 (comment)

Expected behavior
The documentation should include mute_process_user_error: true alongside mute_process_name_error: true so users copying the provided config do not get error spam.

Deployment Type
Self Hosted (Docker)