[DE] Update Help centre/Store/Store archive

[The-Last-Cookie]

The title should be translated.

Related to #12147

• Check if Add link to "Past osu!store items" on Store archive #12388 makes any changes in Store archive

Self-check

• The changes are tested against the contribution checklist
• (translations only) The changes are reviewed on GitHub by a fluent speaker

[The-Last-Cookie]

Waiting for the review by Yannic2112 to come back (his account is [likely temporarily] banned)

[The-Last-Cookie]

The context should be enough for anybody to understand what it is although we could turn osu!store into a link to https://osu.ppy.sh/store/listing

Debatable in my opinion. Users can already access the store via the menu header at the top, and this change is out of scope here anyway because every language would need to be adjusted.

[ghost]

Looks good. No mistakes in the writing and everything has been translated properly.
I think it's ready to be shipped in it's current state.