Add `is_enabled` field to live config announcements

src/api/live_config.py

@@ -41,6 +41,9 @@ class LiveConfig:
                 if visibility not in ["only_main_page", "all_pages", "all_pages_and_embed"]:
                     unsafe_announcement.get("visibility").raise_error("Unknown visibility")
                 text = unsafe_announcement.get_string("text", TYPE_STRING_LONG.get_max_string_length())
+                
+                if not unsafe_announcement.get_bool("is_enabled", True):
+                    continue
                 static_announcements.append({
                     "type": type,
                     "visibility": visibility,