Single capability request call

The active requests page was polling the capability service twice every time and again after clicking on a filter or changing the selected capability. This reduces the number of calls to once per poll.

Note: My lack of JS observable/observer knowledge shows here and I couldn't manage to get the trackActiveRequests event to capture an update to sortedActiveRequests$ after my changes. I'll continue to poke at it but I've already wasted a good chunk of time trying to get filters to apply without reloading the page.

Before (2 requests per poll):

After (1 request per poll):