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/features/video/stateNotice.ts

@@ -26,7 +26,7 @@ export function announceVideoState(
     message: video?.title
       ? msg(hidden ? "feed.hiddenNamed" : "feed.markedWatchedNamed", { title: raw(video.title) })
       : msg(hidden ? "feed.hidden" : "feed.markedWatched"),
-    action: { label: i18n.t(hidden ? "feed.undo" : "feed.unwatch"), onClick: undo },
+    action: { label: msg(hidden ? "feed.undo" : "feed.unwatch"), onClick: undo },
     meta: {
       kind: hidden ? "video-hidden" : "video-watched",
       videoId: id,