[network/konversation] po: Remove outdated translated doc still using a remove entity

[Luigi Toscano]

Git commit aee48ad689fc22448796817ea51bd5f655cd980f by Luigi Toscano.
Committed on 01/10/2023 at 14:51.
Pushed by ltoscano into branch 'master'.

Remove outdated translated doc still using a remove entity

The entity was removed from the source documentation. This will make
it easier to move this to Qt6.

D  +0    -6054 po/de/docs/konversation/index.docbook
D  +0    -6102 po/pt/docs/konversation/index.docbook
D  +0    -6095 po/ru/docs/konversation/index.docbook

https://invent.kde.org/network/konversation/-/commit/aee48ad689fc22448796817ea51bd5f655cd980f