Contacts interactions integration: Translated category leads to weird state when a user changed the language

[kesselb]

Describe the bug

Contacts created by the contacts interactions app were using a translated label for the categories property. That can lead to a weird state when a user changes the language.

Steps to reproduce

1. Send an email or share a file to an address not listed in the recently contacted address book
2. Change the language
3. Repeat the first step
4. See in the contacts app that there's an additional contact group "Zuletzt kontaktiert" (e.g. if you started with english and then switched to german)

Expected behavior

Grouping should work, and no additional contact group is shown.

Actual behavior

Grouping does not work, additional contact group is shown.

Additional info

We actually have two issues here:

1)

When using a non-english-language, the translation for recently contacted is missing. That's addressed by #4662; however, that change does not resolve the actual problem with the grouping, it just flips the view.

2)

The grouping is currently done by the categories property, which isn’t ideal for the contact interactions case. My first idea was to group contact interactions by their address book since that uses the same identifier. However, this would have required a number of changes throughout the app for this special case.

After brainstorming with @hamza221, we agreed that since it’s rather edge-casey, it’s acceptable for now to leave the category untranslated in the vCard and only handle the translation on the frontend. Not perfect for 3rd-party clients, but we’ll see how it goes.

Change in contacts to group on the untranslated string: #4664
Change in server to not translate the strings: nextcloud/server#54736