Add run button to new tests added

[codebytere]

When a new test is added locally, the little green "run" button should be added next to it as it is for existing tests. maybe also a bug? not sure.

[dsanders11]

You can get the run button by refreshing the tests at the top of the test explorer view.

VS Code extension docs suggest refreshing the tests automatically when the test files are modified, but this is tricky for this extension because it's actually a heavy operation to get the list of tests (it has to launch Electron and takes a few seconds), so it's not something that can be done constantly. Not sure what the best balance is here, I've left it to manual refreshing for now, but I agree it's not ideal.