rcon commands in helm config file not working

### Enhancement Type

Improve an existing feature

### Describe the enhancement

rcon commands on startup, first connect, and last disconnect don't seem to apply.

would appreciate it if this compatibility was extended to the helm config unless there is another way to apply these, for example environment variables

```yaml
rcon:
# If you enable this, make SURE to change your password below.
enabled: true
# By default, the container will generate a random password at startup
# to ensure internal RCON tooling, including a backup container,
# can be used, but the password is secure.
withGeneratedPassword: false
port: 25575
rconCmdsStartup: |-
/gamerule doFireTick false
/pregen start 1000
rconCmdsFirstConnect: |-
/pregen stop
rconCmdsLastDisconnect: |-
/pregen start 1000
```

Locate the Helm values and templates that handle rconCmdsStartup, rconCmdsFirstConnect, and rconCmdsLastDisconnect; no specific files or tests are named in the issue. Check how these settings are passed to the server, then verify that each command runs at startup, first connect, and last disconnect using the provided configuration.

Written by the indexing model from the issue text.