chore(release): Changelog for 21.1.4

[nickvergessen]

21.1.4 – 2025-08-28

Added

• feat(sip): Allow to send the direct dial-in number of users on out-going calls #15701
• feat(settings): Add a config for the unread message threshold for the AI summary #15734

Changed

• Update translations
• Update dependencies

Fixed

• fix(dashboard): Fix events without an end date #15732
• fix(chat): Suggest mentioning yourself, it's useful with bots and todos #15656
• fix(chat): Fix search interaction when scrolling away and clicking on a result again #15706
• fix(chat): Fix support for at-all in captions when sharing a file #15744