Update Jar feature not working if server was imported or created from a modpack

[WillTDA]

Description

As the title suggests.
This might affect templates, but unsure.

Steps to Reproduce

Import a server (.cbx) or create a server from a modpack or .mrpack file.

Expected Behaviour

Should show a documented build version number for the server (if supported), like it would if the server was created from scratch.

Actual Behaviour

Does not show a documented version number.

Deployment Method

Docker

Craftbox Version

1.1.0

Browser

n/a

Logs / Screenshots

The build version number can appear after checking for upgrades, but the bug is that sometimes this does not resolve the problem, and there is no build version documented