perrmisions error with disk input

### Relevant telegraf.conf

```toml
Telegraf 1.33.0 (git: HEAD@67902005)
Debian GNU/Linux 12 (bookworm)
Raspberry Pi 5 Model B Rev 1.0

[[inputs.disk]]
## By default stats will be gathered for all mount points.
## Set mount_points will restrict the stats to only the specified mount points.
# mount_points = ["/"]
## Ignore mount points by filesystem type.
ignore_fs = ["tmpfs", "devtmpfs", "devfs", "overlay", "aufs", "squashfs"]
```

### Logs from Telegraf

```text
tcronin:tec-pi-mgr ~:cat /var/log/telegraf/telegraf.log
2024-12-17T05:26:01Z W! Telegraf is not permitted to read /etc/telegraf/telegraf.d
2024-12-17T05:26:01Z I! Loading config: /etc/telegraf/telegraf.conf
2024-12-17T05:26:01Z I! Starting Telegraf 1.33.0 brought to you by InfluxData the makers of InfluxDB
2024-12-17T05:26:01Z I! Available plugins: 236 inputs, 9 aggregators, 33 processors, 26 parsers, 63 outputs, 6 secret-stores
2024-12-17T05:26:01Z I! Loaded inputs: cpu disk diskio exec mem net processes swap system temp
2024-12-17T05:26:01Z I! Loaded aggregators:
2024-12-17T05:26:01Z I! Loaded processors:
2024-12-17T05:26:01Z I! Loaded secretstores:
2024-12-17T05:26:01Z I! Loaded outputs: influxdb_v2
2024-12-17T05:26:01Z I! Tags enabled: host=tec-pi-mgr
2024-12-17T05:26:01Z I! [agent] Config: Interval:10s, Quiet:false, Hostname:"tec-pi-mgr", Flush Interval:10s
2024-12-17T05:26:01Z D! [agent] Initializing plugins
2024-12-17T05:26:01Z W! DeprecationWarning: Value "false" for option "ignore_protocol_stats" of plugin "inputs.net" deprecated since version 1.27.3 and will be removed in 1.36.0: use the 'inputs.nstat' plugin instead for protocol stats
2024-12-17T05:26:01Z D! [agent] Connecting outputs
2024-12-17T05:26:01Z D! [agent] Attempting connection to [outputs.influxdb_v2]
2024-12-17T05:26:01Z D! [agent] Successfully connected to outputs.influxdb_v2
2024-12-17T05:26:01Z D! [agent] Starting service inputs
2024-12-17T05:26:10Z D! [inputs.disk] [SystemPS] => unable to get disk usage ("/run/credentials/systemd-sysctl.service"): permission denied
2024-12-17T05:26:10Z D! [inputs.disk] [SystemPS] => unable to get disk usage ("/run/credentials/systemd-sysusers.service"): permission denied
2024-12-17T05:26:10Z D! [inputs.disk] [SystemPS] => unable to get disk usage ("/run/credentials/systemd-tmpfiles-setup-dev.service"): permission denied
2024-12-17T05:26:10Z D! [inputs.disk] [SystemPS] => unable to get disk usage ("/run/credentials/systemd-tmpfiles-setup.service"): permission denied
2024-12-17T05:26:11Z D! [outputs.influxdb_v2] Wrote batch of 23 metrics in 15.359162ms
2024-12-17T05:26:11Z D! [outputs.influxdb_v2] Buffer fullness: 0 / 10000 metrics
```

### System info

Telegraf 1.33.0 (git: HEAD@67902005) Debian GNU/Linux 12 (bookworm) Raspberry Pi 5 Model B Rev 1.0

### Docker

direct install on raspberry PI

### Steps to reproduce

run telegraf via systemd

### Expected behavior

no error in logs

### Actual behavior

2024-12-17T05:26:30Z D! [inputs.disk] [SystemPS] => unable to get disk usage ("/run/credentials/systemd-sysctl.service"): permission denied
2024-12-17T05:26:30Z D! [inputs.disk] [SystemPS] => unable to get disk usage ("/run/credentials/systemd-sysusers.service"): permission denied
2024-12-17T05:26:30Z D! [inputs.disk] [SystemPS] => unable to get disk usage ("/run/credentials/systemd-tmpfiles-setup-dev.service"): permission denied
2024-12-17T05:26:30Z D! [inputs.disk] [SystemPS] => unable to get disk usage ("/run/credentials/systemd-tmpfiles-setup.service"): permission denied

### Additional info

setup was generated from the following template

https://github.com/influxdata/community-templates/tree/master/raspberry-pi

Start with the inputs.disk plugin and reproduce the reported behavior by running Telegraf via systemd on Debian 12 with the shown configuration. Compare the resulting logs with the expected behavior: the permission-denied messages for the listed /run/credentials paths should no longer appear.

Written by the indexing model from the issue text.