chore(talk/conversations): refresh screenshots for NC34

Regenerated via Playwright automation (feat/screenshot-automation).
22 images updated: talk-dashboard, note-to-self, one-to-one-right-sidebar,
one-to-one-extend, create-new-conversation, creating-open-conversation,
add-participants, new-room, filters-menu, clear-filter, group-public-settings,
participant-menu, open-settings, conversation-settings-dialog,
messages-expiration, ban-participant, ban-participant-dialog,
ban-participant-list, conversation-notifications, privacy-settings,
archived-conversations-button, archived-conversations-list.

AI-Assisted-By: Claude Sonnet 4.6 <claude@anthropic.com>
Signed-off-by: Anna Larch <anna@nextcloud.com>

Author: miaulalala