flip bell-indicator to true by default (#3023)

Author: sawka

pkg/wconfig/defaultconfig/settings.json

@@ -29,7 +29,7 @@
     "window:savelastwindow": true,
     "telemetry:enabled": true,
     "term:bellsound": false,
-    "term:bellindicator": false,
+    "term:bellindicator": true,
     "term:osc52": "always",
     "term:cursor": "block",
     "term:cursorblink": false,