debugger: Fix issues with launch.json handling (#32563)

After this PR we can run all the in-tree launch.json examples from [this
repo](https://github.com/microsoft/vscode-recipes).

Things done:

- Fill in default cwd at a lower level for all adapters
- Update launch.json parsing for DebugScenario changes
- Imitate how VS Code normalizes the `type` field for JS debug tasks
- Make version field optional
- Extend the variable replacer a bit

Release Notes:

- Debugger Beta: fixed issues preventing loading and running of debug
tasks from VS Code's launch.json.

---------

Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Anthony <anthony@zed.dev>
Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/dap_adapters/src/python.rs

@@ -83,6 +83,7 @@ impl PythonDebugAdapter {
 
     fn request_args(
         &self,
+        delegate: &Arc<dyn DapDelegate>,
         task_definition: &DebugTaskDefinition,
     ) -> Result<StartDebuggingRequestArguments> {
         let request = self.request_kind(&task_definition.config)?;
@@ -95,6 +96,11 @@ impl PythonDebugAdapter {
             }
         }
 
+        if let Some(obj) = configuration.as_object_mut() {
+            obj.entry("cwd")
+                .or_insert(delegate.worktree_root_path().to_string_lossy().into());
+        }
+
         Ok(StartDebuggingRequestArguments {
             configuration,
             request,
@@ -196,7 +202,7 @@ impl PythonDebugAdapter {
             }),
             cwd: Some(delegate.worktree_root_path().to_path_buf()),
             envs: HashMap::default(),
-            request_args: self.request_args(config)?,
+            request_args: self.request_args(delegate, config)?,
         })
     }
 }