[ticket/12534] Do not abuse errorbox for en/disable confirmation of extensions

PHPBB3-12534
[ticket/12534] Do not use errorbox for multi steps

PHPBB3-12534
[ticket/12534] Fix filter for functional tests

PHPBB3-12534
Merge remote-tracking branch 'nickvergessen/ticket/12534' into develop-ascraeus

* nickvergessen/ticket/12534:
  [ticket/12534] Fix filter for functional tests
  [ticket/12534] Do not use errorbox for multi steps
  [ticket/12534] Do not abuse errorbox for en/disable confirmation of extensions
[ticket/12519] Restore m_approve language description

Restore acl_m_approve language description to:
"Can approve and restore posts"

PHPBB3-12519
Merge pull request #2452 from n-aleha/ticket/12519

[ticket/12519] Restore m_approve language description

* n-aleha/ticket/12519:
  [ticket/12519] Restore m_approve language description
[ticket/12544] Update Plupload to 2.1.2.

PHPBB3-12544
Merge pull request #2457 from prototech/ticket/12544

[ticket/12544] Update Plupload to 2.1.2.

* prototech/ticket/12544:
  [ticket/12544] Update Plupload to 2.1.2.