refactor: improve TypeScript patterns in test files (Group 1/8) (#8253)

## Summary
Improves type safety in test files by replacing unsafe type patterns
with proper TypeScript idioms.

## Changes
- Define typed `TestWindow` interface extending `Window` for Playwright
tests with custom properties
- Use `Partial<HTMLElement>` with single type assertion for DOM element
mocks
- Remove redundant type imports
- Fix `console.log` → `console.warn` in test fixture

## Files Changed
16 test files across browser_tests, packages, and src/components

## Test Plan
- ✅ `pnpm typecheck` passes
- ✅ No new `any` types introduced
- ✅ All pre-commit hooks pass

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8253-refactor-improve-TypeScript-patterns-in-test-files-Group-1-8-2f16d73d365081548f9ece7bcf0525ee)
by [Unito](https://www.unito.io)

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/components/common/UserAvatar.test.ts

@@ -1,3 +1,5 @@
+import type { ComponentProps } from 'vue-component-type-helpers'
+
 import { mount } from '@vue/test-utils'
 import Avatar from 'primevue/avatar'
 import PrimeVue from 'primevue/config'
@@ -27,7 +29,7 @@ describe('UserAvatar', () => {
     app.use(PrimeVue)
   })
 
-  const mountComponent = (props: any = {}) => {
+  const mountComponent = (props: ComponentProps<typeof UserAvatar> = {}) => {
     return mount(UserAvatar, {
       global: {
         plugins: [PrimeVue, i18n],