🩹(frontend) remove warning on modal without heading

The MuteAlertDialog was triggering accessibility warnings, lacking
a proper heading. Fix it.

src/frontend/src/features/rooms/livekit/components/MuteAlertDialog.tsx

@@ -17,7 +17,11 @@ export const MuteAlertDialog = ({
     keyPrefix: 'participants.muteParticipantAlert',
   })
   return (
-    <Dialog isOpen={isOpen} role="alertdialog">
+    <Dialog
+      isOpen={isOpen}
+      role="alertdialog"
+      aria-label={t('heading', { name })}
+    >
       <P>{t('description', { name })}</P>
       <HStack gap={1}>
         <Button variant="text" size="sm" onPress={onClose}>

src/frontend/src/locales/de/rooms.json

@@ -179,6 +179,7 @@
     "muteYourself": "",
     "muteParticipant": "",
     "muteParticipantAlert": {
+      "heading": "",
       "description": "",
       "confirm": "",
       "cancel": ""

src/frontend/src/locales/en/rooms.json

@@ -178,6 +178,7 @@
     "muteYourself": "Close your mic",
     "muteParticipant": "Close the mic of {{name}}",
     "muteParticipantAlert": {
+      "heading": "Mute {{name}}",
       "description": "Mute {{name}} for all participants? {{name}} will be the only one who can unmute themselves.",
       "confirm": "Mute",
       "cancel": "Cancel"

src/frontend/src/locales/fr/rooms.json

@@ -178,6 +178,7 @@
     "muteYourself": "Couper votre micro",
     "muteParticipant": "Couper le micro de {{name}}",
     "muteParticipantAlert": {
+      "heading": "Couper le micro de {{name}}",
       "description": "Couper le micro de {{name}} pour tous les participants ? {{name}} est la seule personne habilitée à réactiver son micro",
       "confirm": "Couper le micro",
       "cancel": "Annuler"