Fix/more missing userid cases

[salmart-dev]

Summary

Sets the user id header in DAV responses in beforeMethod instead of afterMethod, this ensures that if some plugins stop the event propagation, the user id header will still be set.

Adds the same header in the redirect response when calling GET /index.php which redirects to the default app.

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)