Variant items aren’t targetable by missions

### Describe the bug

If you use a specific variants ID in a mission goal tests will fail. Missions predate variant items so that explains potentially why.

### Attach save file

N/A

### Steps to reproduce

Open a PR with a mission targeting a variant item. Watch CI fail.

### Expected behavior

Variant items to be supported.

### Screenshots

_No response_

### Versions and configuration

Current CI

### Additional context

Need to link my PR currently failing to this issue but on phone right now.

The issue names no files, tests, or entry points. Start by reproducing the CI failure with a mission targeting a variant item and trace the mission-goal validation path. Done means missions can target variant items and the affected CI checks pass.

Written by the indexing model from the issue text.