[Bug]: reflected lit properties don't work in the manager electron application

Application

Outline Manager

Describe the bug

When you use lit's reflected properties in isolation they work, but for some reason they get removed by/don't work in the the electron app. See fix: https://github.com/Jigsaw-Code/outline-apps/pull/2399

Steps to reproduce

Revert the above PR and then induce a data limit warning by modifying the app#refreshServerMetricsUI method.