python: Init venv/virtualenv activation scripts during list/resolve (#40816)

This means that existence of activation scripts for venv/virtualenv will
be checked locally either on the host if editing locally, or the remote
by the remote proxy if editing a remote project.

Closes https://github.com/zed-industries/zed/issues/40263

Release Notes:

- N/A

crates/remote_server/src/headless_project.rs

@@ -102,6 +102,7 @@ impl HeadlessProject {
                 worktree_store.clone(),
                 environment.clone(),
                 manifest_tree.clone(),
+                fs.clone(),
                 cx,
             )
         });