Fix device change detection.

Refresh worker not properly implemented - did not have access to current proxy client state.

Intended behaviour:
- continuously check list of devices when in DEVICES, START_TRACE or CONNECTING state
- restart the timer (if appropriate based on proxy state) when navigating back to homepage from trace view page

Screencast: https://screencast.googleplex.com/cast/NjA5NjgzMDE0NzMzMDA0OHwwNDU1MDA2ZS05MA

Fixes: 259539295
Test: npm run test:unit:ci

Change-Id: I1576fc548c6f6b63177703ca0b3142beddfa24c7
2 files changed