error fetching io.pressure in agent logs even when only using prometheus policy

I'm running agent inside docker via this docker-compose configuration https://github.com/matschaffer/elastic-otel-metrics/blob/main/docker-compose.yml#L4-L9

The agent is being enrolled into a "prometheus-otel" polic that I create than only has the prometheus metrics integration.

Here's the full policy:

prometheus-otel.policy.yml

```
id: f028f2d0-c461-11ec-befe-036853398716
revision: 4
outputs:
default:
type: elasticsearch
hosts:
- >-
https://REDACTED.asia-northeast1.gcp.cloud.es.io:443
output_permissions:
default:
_elastic_agent_monitoring:
indices:
- names:
- logs-elastic_agent.apm_server-default
privileges: &ref_0
- auto_configure
- create_doc
- names:
- metrics-elastic_agent.apm_server-default
privileges: *ref_0
- names:
- logs-elastic_agent.auditbeat-default
privileges: *ref_0
- names:
- metrics-elastic_agent.auditbeat-default
privileges: *ref_0
- names:
- logs-elastic_agent-default
privileges: *ref_0
- names:
- metrics-elastic_agent.elastic_agent-default
privileges: *ref_0
- names:
- metrics-elastic_agent.endpoint_security-default
privileges: *ref_0
- names:
- logs-elastic_agent.endpoint_security-default
privileges: *ref_0
- names:
- logs-elastic_agent.filebeat-default
privileges: *ref_0
- names:
- metrics-elastic_agent.filebeat-default
privileges: *ref_0
- names:
- logs-elastic_agent.fleet_server-default
privileges: *ref_0
- names:
- metrics-elastic_agent.fleet_server-default
privileges: *ref_0
- names:
- logs-elastic_agent.heartbeat-default
privileges: *ref_0
- names:
- metrics-elastic_agent.heartbeat-default
privileges: *ref_0
- names:
- logs-elastic_agent.metricbeat-default
privileges: *ref_0
- names:
- metrics-elastic_agent.metricbeat-default
privileges: *ref_0
- names:
- logs-elastic_agent.osquerybeat-default
privileges: *ref_0
- names:
- metrics-elastic_agent.osquerybeat-default
privileges: *ref_0
- names:
- logs-elastic_agent.packetbeat-default
privileges: *ref_0
- names:
- metrics-elastic_agent.packetbeat-default
privileges: *ref_0
_elastic_agent_checks:
cluster:
- monitor
prometheus-otel-docker:
indices:
- names:
- metrics-prometheus.collector-default
privileges: *ref_0
agent:
monitoring:
enabled: true
use_output: default
namespace: default
logs: true
metrics: true
inputs:
- id: prometheus/metrics-prometheus-b0d13fc8-b1c4-4ef9-b1c9-2ae8c2e448a2
name: prometheus-otel-docker
revision: 2
type: prometheus/metrics
use_output: default
meta:
package:
name: prometheus
version: 0.7.0
data_stream:
namespace: default
streams:
- id: >-
prometheus/metrics-prometheus.collector-b0d13fc8-b1c4-4ef9-b1c9-2ae8c2e448a2
data_stream:
dataset: prometheus.collector
type: metrics
metrics_filters.exclude: null
password: ''
period: 10s
hosts:
- 'host.docker.internal:9464'
metricsets:
- collector
ssl.certificate_authorities: null
use_types: true
bearer_token_file: ''
metrics_filters.include: null
rate_counters: true
metrics_path: /metrics
username: ''
fleet:
hosts:
- >-
https://REDACTED.fleet.asia-northeast1.gcp.cloud.es.io:443
```

When I do this the logs are full of this error:

```
{"log.level":"error","@timestamp":"2022-04-26T02:34:20.691Z","log.origin":{"file.name":"metrics/metrics.go","file.line":382},"message":"error getting cgroup stats: error fetching stats for controller io: error fetching IO stats: error fetching io.pressure for path /sys/fs/cgroup:: open /sys/fs/cgroup/io.pressure: no such file or directory","ecs.version":"1.6.0"}
```

I see that `agent.monitoring.enabled` is true, so perhaps something in that code is attempting to fetch cgroup io pressure info?

I'm running on macOS with docker for mac on an intel chipset.