[stable32] fix(ContactsManager): Fix conflict with value type from database

[solracsf]

Summary

⚠️ UNIFIED SEARCH STOPPED WORKING

1. Try a search (search never returns results)
2. Observe search console (and Nextcloud error log)

Regression from #55657
Cc @artonge

Fixes:

# occ config:app:get dav system_addressbook_exposed
no

"Exception": "OCP\\Exceptions\\AppConfigTypeConflictException",
    "Message": "conflict with value type from database",
    "Code": 0,
    "Trace": [
      {
        "file": "/var/www/nextcloud/lib/private/AppConfig.php",
        "line": 413,
        "function": "getTypedValue",
        "class": "OC\\AppConfig",
        "type": "->",
        "args": [
          "dav",
          "system_addressbook_exposed",
          "true",
          false,
          32
        ]
      },
      {
        "file": "/var/www/nextcloud/apps/dav/lib/CardDAV/ContactsManager.php",
        "line": 48,
        "function": "getValueBool",
        "class": "OC\\AppConfig",
        "type": "->",
        "args": [
          "dav",
          "system_addressbook_exposed",
          true
        ]
      },

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)

[solracsf]

If this get merged, should be backported until stable28 like original commit d14c96b

PS: #55657 should also be reviewed (for master, not same codebase)

[susnux]

But this wrongly writes a string? This sounds more like there is a place where it explicitly is written as string (legacy app config writes as mixed which should be ok?), no?