dap: Allow user to pass custom envs to adapter via project settings (#40490)

It is now possible to configure logging level of CodeLLDB adapter via
envs specified in project settings like so:

```
{
    "dap": {
        "CodeLLDB": {
            "envs": {
                "RUST_LOG": "debug"
            }
        }
    }
}
```

Release Notes:

- N/A

crates/project/src/debugger/dap_store.rs

@@ -264,13 +264,21 @@ impl DapStore {
                     DapBinary::Custom(binary) => Some(PathBuf::from(binary)),
                 });
                 let user_args = dap_settings.map(|s| s.args.clone());
+                let user_env = dap_settings.map(|s| s.env.clone());
 
                 let delegate = self.delegate(worktree, console, cx);
                 let cwd: Arc<Path> = worktree.read(cx).abs_path().as_ref().into();
 
                 cx.spawn(async move |this, cx| {
                     let mut binary = adapter
-                        .get_binary(&delegate, &definition, user_installed_path, user_args, cx)
+                        .get_binary(
+                            &delegate,
+                            &definition,
+                            user_installed_path,
+                            user_args,
+                            user_env,
+                            cx,
+                        )
                         .await?;
 
                     let env = this

crates/project/src/project_settings.rs

@@ -1215,6 +1215,7 @@ pub fn local_settings_kind_to_proto(kind: LocalSettingsKind) -> proto::LocalSett
 pub struct DapSettings {
     pub binary: DapBinary,
     pub args: Vec<String>,
+    pub env: HashMap<String, String>,
 }
 
 impl From<DapSettingsContent> for DapSettings {
@@ -1224,6 +1225,7 @@ impl From<DapSettingsContent> for DapSettings {
                 .binary
                 .map_or_else(|| DapBinary::Default, |binary| DapBinary::Custom(binary)),
             args: content.args.unwrap_or_default(),
+            env: content.env.unwrap_or_default(),
         }
     }
 }