Refresh diagnostics when Studio plugin connects

[lolmanurfunny]

Upon startup, the server always emits a few type errors since A) the studio plugin hasn't connected to the server and B) my codebase depends on strictDatamodelTypes.

It's a bit annoying because the server doesn't update the diagnostics in response to receiving the DM info, instead the user must perform some action, like editing the contents of a script, switching to a different file, etc.