Fix incorrect German translation for DELETE_MESSAGE

[Cankiee]

Pull Request Description

This change corrects the translation for the DELETE_MESSAGE key in the localization file. Previously, it was translated as "Gelöschte Nachricht", which corresponds to "Deleted message" and describes a state rather than an action. The updated translation, "Nachricht löschen", correctly reflects the intended action of deleting a message, ensuring consistency with the original meaning and aligning with common German UI terminology.

Pull Request Checklist:

• Have you followed the guidelines in our Contributing document and Code of Conduct?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
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