fix(apporder): Load custom app order before resolving closures

[nickvergessen]

• Resolves: Hardcoded app order value overwrites user-set app order spreed#16678

Summary

Ref: nextcloud/spreed#16678 (comment)

It required an app that registers a page alphabetically after Talk (spreed) via the add method (closure or not does not matter).
The problem is this resolves the closure of Talk, but does not load the custom app order before, so Talk is still -5.

Steps

1. Enable Talk
2. Enable thesearchpage app, external app, or something similar
3. Change app order and move Talk lower
4. Talk is still first

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI

[nickvergessen]

/backport to stable33

[nickvergessen]

/backport to stable32