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/lib/notifications.ts

@@ -66,7 +66,8 @@ const LOG_LEVEL: Record<NotifLevel, Level> = {
 export type NotifLevel = "info" | "success" | "warning" | "error" | "fatal";
 
 interface NotifAction {
-  label: string;
+  // Said when shown, like the notice's text: a language switch must not leave the button behind.
+  label: NotifText;
   onClick: () => void;
 }