Inconsistent behavior when manipulating app args

[jdknives]

Describe the bug

When setting the secure mode for the VPN-server via HypervisorUI and without setting a password, the hypervisor UI adds these values

		"name": "vpn-server",
				"args": [
					"-passcode",
					"",
					"-secure",
					"true"
				],

This leads to the VPN-server not registering itself in the service discovery because the check we perform is not sufficient. This needs to be fixed.

When unchecking the box of secure mode again, this is the updated config value:

	"name": "vpn-server",
				"args": [
					"-secure",
					"false"
				],

This is probably not the best way to deal with it. Imo, it sounds cleaner to generate the default values at config generation and always update all of the values when manipulating at least one of them via the hypervisor. The check for whether the VPN is password protected needs to be improved to actually check whether the password is non-empty instead of just checking if the arg is present.