Chore: Upgrade Vitest to v4 (#7797)

## Summary

https://vitest.dev/guide/migration.html#vitest-4

## Changes

- **What**: Update Vitest and some associated dependencies
- **What**: Fix issue with our existing mocks and mock types

## Review Focus

Double check the test updates. I tried to keep the changes minimal.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7797-Chore-Upgrade-Vitest-to-v4-2d96d73d3650810cbe3ac42d7bd6585a)
by [Unito](https://www.unito.io)

---------

Co-authored-by: GitHub Action <action@github.com>

tests-ui/tests/services/keybindingService.escape.test.ts

@@ -26,15 +26,15 @@ vi.mock('@/stores/dialogStore', () => ({
 
 describe('keybindingService - Escape key handling', () => {
   let keybindingService: ReturnType<typeof useKeybindingService>
-  let mockCommandExecute: ReturnType<typeof vi.fn>
+  let mockCommandExecute: ReturnType<typeof useCommandStore>['execute']
 
   beforeEach(() => {
     vi.clearAllMocks()
     setActivePinia(createPinia())
 
     // Mock command store execute
-    mockCommandExecute = vi.fn()
     const commandStore = useCommandStore()
+    mockCommandExecute = vi.fn()
     commandStore.execute = mockCommandExecute
 
     // Reset dialog store mock to empty