fix: Update HappyDOMOptions to be compatible with v12 (#4135)

Author: anthonyblond

packages/vitest/src/types/happy-dom-options.ts

@@ -12,6 +12,9 @@ export interface HappyDOMOptions {
     disableIframePageLoading?: boolean
     disableComputedStyleRendering?: boolean
     enableFileSystemHttpRequests?: boolean
+    navigator?: {
+      userAgent?: string
+    }
     device?: {
       prefersColorScheme?: string
       mediaType?: string