fix(global-search): Fix documented default config value

[nickvergessen]

• Ref

  server/lib/private/TemplateLayout.php

  Line 113 in 13d03f4

  if ($this->config->getSystemValueBool('unified_search.enabled', 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)

[jospoortvliet]

LGTM 🐘 ✨

[blizzz]

So i was rightfully confused about the naming and value :)