Fix/campaign restrictions

[lL1l1]

Description of the proposed changes

Fixes #6675.
Only repair orders are permitted to bypass campaign restrictions, since they do not create a new unit.

Testing done on the proposed changes

• Start the aeon tutorial campaign mission ("Joust") using the coop dev environment (set location of repo in init_coop.lua and run coop init), and run the following command with a mass extractor selected:

local unit = GetSelectedUnits()[1]
IssueBlueprintCommandToUnit(
    unit, "UNITCOMMAND_Upgrade",
    unit:GetBlueprint().General.UpgradesTo,
    1, true
)

It logs a warning and doesn't upgrade.

Checklist

• Changes are annotated, including comments where useful
• Changes are documented in the changelog for the next game version