Add warning/note when removing devices (#5580)

Part of https://github.com/element-hq/matrix-authentication-service/issues/4339 / https://github.com/element-hq/backend-internal/issues/199 tracking work to limit number of devices.

frontend/locales/en.json

@@ -102,7 +102,8 @@
       "heading": "The email address {{email}} is already in use."
     },
     "end_session_button": {
-      "confirmation_modal_title": "Are you sure you want to end this session?",
+      "confirmation_modal_body_text": "Make sure you always have access to another verified device or your recovery key to avoid losing your encrypted chat history.",
+      "confirmation_modal_title": "Are you sure you want to remove this device?",
       "text": "Remove device"
     },
     "error": {

frontend/src/components/Session/EndSessionButton.tsx

@@ -44,6 +44,10 @@ const EndSessionButton: React.FC<
         {t("frontend.end_session_button.confirmation_modal_title")}
       </Dialog.Title>
 
+      <Dialog.Description>
+        {t("frontend.end_session_button.confirmation_modal_body_text")}
+      </Dialog.Description>
+
       {children && <Dialog.Description asChild>{children}</Dialog.Description>}
 
       <Button