Fixed that text/plain attachments are added to issue description (#15684).

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extra : convert_revision : svn%3Ae93f8b46-1217-0410-a6f0-8f06a7374b81/trunk%4012420
Fixed that time entries custom values are not deleted when deleting a project or an issue (#15709).

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extra : convert_revision : svn%3Ae93f8b46-1217-0410-a6f0-8f06a7374b81/trunk%4012421