Fix non-Promise values in Promise.all in extension.ts

This commit fixes incorrect usage of Promise.all() where non-Promise
values were being passed, causing ESLint errors.

Problem:
The restartQueryServer command was passing an array to Promise.all()
containing:
1. A Promise (queryRunner.restartQueryServer)
2. Either a Promise or an empty object {} (conditional expression)
3. An async function (not invoked, so not a Promise)

ESLint rule '@typescript-eslint/await-thenable' detected this error:
  src/extension.ts:200:11
  Unexpected iterable of non-Promise (non-"Thenable") values passed
  to promise aggregator

The issues were:
- Line 199: Using `{}` as a fallback instead of a resolved Promise
- Line 200: Declaring an async function but not invoking it (missing
  the `()` to actually call the function and get its Promise)

Solution:
1. Replace `{}` with `Promise.resolve()` to maintain type consistency
2. Wrap the async function in an IIFE (Immediately Invoked Function
   Expression) by adding `()` at the end: `(async () => { ... })()`

This ensures Promise.all() receives an array of actual Promise objects,
allowing it to properly await all operations in parallel.

File modified:
- extensions/ql-vscode/src/extension.ts

Author: d10c

extensions/ql-vscode/src/extension.ts

@@ -196,14 +196,14 @@ function getCommands(
           queryRunner.restartQueryServer(progress),
           queryRunnerForWarmingOverlayBaseCache
             ? queryRunnerForWarmingOverlayBaseCache.restartQueryServer(progress)
-            : {},
-          async () => {
+            : Promise.resolve(),
+          (async () => {
             if (languageClient.isRunning()) {
               await languageClient.restart();
             } else {
               await languageClient.start();
             }
-          },
+          })(),
         ]);
         void showAndLogInformationMessage(
           queryServerLogger,