fix: page content's get_absolute_url needs to return URL of page content's language

[fsbraun]

Description

The page content's get_absolute_url should return the URL of the page content object, i.e. in the page content's language.

This is relevant, for example, for the "View published" button in versioning.

Underlying issue

With the current language being, say, English, clicking "View published" for a page content object in a different language will lead to the English published URL.

Checklist

• I have opened this pull request against develop-4
• I have added or modified the tests when changing logic
• I have followed the conventional commits guidelines to add meaningful information into the changelog
• I have read the contribution guidelines and I have joined #workgroup-pr-review on Slack to find a “pr review buddy” who is going to review my pull request.

[marksweb]

LGTM