Enhance desktop access troubleshooting (#13980)
Enhance desktop access troubleshooting (#13980)

* Enhance desktop access troubleshooting

Add a section for verifying the Teleport cert was installed correctly,
and mention the error that occurs if NLA is not disabled.

* Address review feedback
gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport