LSP - Understand npm workspaces

[dsherret]

I believe the lsp doesn't understand npm workspaces at the moment.

• Need to implement this for the lsp too when not byonm: fix(workspace): support resolving bare specifiers to npm pkgs within a workspace #24611

When implementing this, I think we should get the lsp code using deno_config::workspace::Workspace:: discover so that we have a single implementation of workspace discovery.