no config debug: Fix error when multiple vscode windows are open

[Zentrik]

Should fix #916, but getting this installed locally seemed sufficiently complicated that I gave up. I figured out the nox stuff, I tested with two windows and this worked.
Fix is:

1. Only watch a specific endpoint file
2. Make sure this endpoint file is unique (I imagine the workspace file path can be non unique across vscode windows)

[rchiodo]

Whoops, didn't meant to close this. @Zentrik it looks like this is causing a bunch of test failures.

[Zentrik]

@Zentrik it looks like this is causing a bunch of test failures.

Sorry about that, thanks for reviewing. I think it should be fixed now, o/w will have to wait till tmrw and I'll boot into windows to debug further.

[Zentrik]

Including the workspace part of the hash seems unnecessary given the inclusion of the sessionId so I removed it, with the added benefit that we now don't have to throw an error if no workspace folder is found. Including the sessionId in the hash does mean that the VSCODE_DEBUGPY_ADAPTER_ENDPOINTS env var changes if you reload the window/extension, but I couldn't see a way around that other than accepting that VSCODE_DEBUGPY_ADAPTER_ENDPOINTS might not be unique.