fix(notifications): a notice's button is said when shown, like its text

An action label was translated when the notice was raised, so after a language switch a live
toast or center row read in one language with its button in the other. The access-requests nudge
no longer re-issues on a switch for it. New tests: the button and a server refusal follow a
switch.

frontend/src/modules/channels/useWatchedChannelActions.ts

@@ -44,7 +44,7 @@ export function useWatchedChannelActions(onOpenWizard: () => void) {
       notify({
         level: "success",
         message: msg("channels.watched.dismissed", { name: raw(nameOf(c)) }),
-        action: { label: t("common.undo"), onClick: () => restore.mutate(c) },
+        action: { label: msg("common.undo"), onClick: () => restore.mutate(c) },
       });
     },
   });