fix: remove the reset-to-defaults button from tag settings

If you carefully crafted your tags and then click this button by accident, all
your hard work is gone. A confirmation message would be the other solution but
since I have difficulty to grasp when you would need such a button, I propose
to just remove it.

locales/da/common.json

@@ -1019,7 +1019,6 @@
       "title": "E-mail-tags",
       "description": "Definér tags til at organisere dine e-mails med farver. Disse gemmes som JMAP-nøgleord på serveren.",
       "add_keyword": "Tilføj tag",
-      "reset_defaults": "Nulstil til standard",
       "label_field": "Visningsnavn",
       "label_placeholder": "f.eks. Arbejde, Privat, Vigtigt",
       "id_field": "Tag-ID",