osctrl-admin SIGSEGV when `_SERVICE` is undefined

[CptOfEvilMinions]

I know _SERVICE_NAME should be admin. However, when if this value is not set the osctrl-admin component SIGSEGV. An output should be generated that config is invalid.

service.json:

{
  "_SERVICE_NAME": {
    "listener": "0.0.0.0",
    "port": "9001",
    "host": "0.0.0.0",
    "auth": "db",
    "logger": "stdout"
  }
}

error output:

osctrl@ubuntuvm:/home/superadmin$ /usr/local/bin/osctrl-admin \                                                                                                                                    --config \
    --config-file /etc/osctrl/osctrl-admin/service.json \
    --redis \
    --redis-file /etc/osctrl/redis.json \
    --db \
    --db-file /etc/osctrl/db.json \
    --jwt \
    --jwt-file /etc/osctrl/osctrl-admin/jwt.json \
    --carved /var/osctrl/carves \
    --templates /usr/share/osctrl/tmpl_admin \
    --static /usr/share/osctrl/static \
    --osquery-tables /etc/osctrl/osctrl-admin/osquery-5.2.2.json
main.go:176: Loading /etc/osctrl/osctrl-admin/service.json
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x160 pc=0x89aab8]

goroutine 1 [running]:
github.com/spf13/viper.(*Viper).AllKeys(0x0)
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/viper.go:1960 +0x98
github.com/spf13/viper.(*Viper).AllSettings(0x0)
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/viper.go:2041 +0x48
github.com/spf13/viper.(*Viper).Unmarshal(0xc00024e000?, {0xb531e0, 0xc00012c9c0}, {0x0, 0x0, 0x0})
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/viper.go:1043 +0x32
main.loadConfiguration({0x7ffc7fc4d6ae, 0x25}, {0xc66c00, 0x5})
	/home/runner/work/osctrl/osctrl/admin/main.go:184 +0x145
main.cliAction(0xc000170b00?)
	/home/runner/work/osctrl/osctrl/admin/main.go:772 +0x74
github.com/urfave/cli/v2.(*App).RunContext(0xc00024e340, {0xd91fa8?, 0xc00011c000}, {0xc000114160, 0x15, 0x16})
	/home/runner/go/pkg/mod/github.com/urfave/cli/[email protected]/app.go:322 +0x953
github.com/urfave/cli/v2.(*App).Run(...)
	/home/runner/go/pkg/mod/github.com/urfave/cli/[email protected]/app.go:224
main.main()
	/home/runner/work/osctrl/osctrl/admin/main.go:832 +0x23e