Toggle Workspace Coverage fails

[mykter]

This might be a dupe of #41, but this is for Workspace coverage rather than Evaluation.

My failure mode is also a bit different to the issue described there - when I hit toggle it clears the output pane. The 'Test Workspace' command works (the output pane shows all of the tests).

The remote extension host output includes

[2021-05-25 17:01:15.896] [exthost] [error] [tsandall.opa] provider FAILED
[2021-05-25 17:01:15.896] [exthost] [error] {"code":"oracle_no_definition_found"}

It's also not obvious to me whether coverage is meant to be on or not - "toggle" is fine if it's clear what your current state is but if there's no indicator then you just have to hit it twice!