feat(Turborepo): return invalid states from package discovery (#7789)

### Description

 - Returns errors when package watching is in a known-invalid state. This means the client does not need to rely on timeouts when we cannot find a package manager or valid workspace globs.
 - Combines the two bits of state, package manager and workspaces, into a single API call. They were effectively already used that way, but now the clients are updated to only make a single call.

### Testing Instructions

Updated tests to no longer use a timeout, as we can now confirm error responses

Closes TURBO-2665