grafana cli: ignores --config argument

[jelmd]

What happened?

When running grafana cli --config $CONF_FILE --homepath /usr/share/grafana plugins ls or similar commands, grafana ignores the --config argument and thus it doesn't find any plugins. Verified this using strace, which shows, that grafana neither tries to open nor to stat the file. Output:

no installed plugins found

What did you expect to happen?

The cli tool should read the config file and honor its paths section, i.e. especially the plugins setting, which points in my case to /data/grafana/plugins. Because of

# ls -al /data/grafana/plugins
total 35
drwxr-xr-x 3 oper staff   3 Dec 16  2020 .
drwxr-x--- 5 oper daemon  7 Feb 28 05:28 ..
drwxr-xr-x 7 oper staff  18 Oct 27  2020 briangann-gauge-panel

it should be able to detect and upgrade the plugin.

### Did this work before?

Just trying to upgrade from v9.3.1 - so not sure.

### How do we reproduce it?

1. Install grafana
2. mkdir /data/grafana/{data,plugins}
3. cp -r /usr/share/grafana/conf/* /data/grafana/
4. rm /data/grafana/{defaults.ini,ldap_multiple.toml}
5. sed -e 's|^;data =.*|data = /data/grafana/data|' -e 's|^;plugins =.*|plugins = /data/grafana/plugins|' -e 's|^;provisioning =.*|provisioning = /data/grafana/provisioning|  /data/grafana/sample.ini >/data/grafana/grafana.ini
6. Run and install a plugin, e.g. `grafana server --config=/data/grafana/grafana.ini --homedir=/usr/share/grafana`
7. Stop the server (^C)
8. Try to find the installed plugin, e.g. `grafana cli --config=/data/grafana/grafana.ini --homedir=/usr/share/grafana plugins ls`

### Is the bug inside a dashboard panel?

Nope

### Environment (with versions)?

Grafana: v9.5.21
OS: Ubuntu 20.04.6 (focal)
Browser: FF


### Grafana platform?

A downloaded binary

### Datasource(s)?

no