Fix: Change Playwright browser tool from sync to async (#17808)

...integrations/tools/llama-index-tools-playwright/README.md

...rations/tools/llama-index-tools-playwright/examples/BUILD

...-tools-playwright/examples/playwright_browser_agent.ipynb

...ols/llama-index-tools-playwright/examples/web_browsing.py

...dex-tools-playwright/llama_index/tools/playwright/base.py

...rations/tools/llama-index-tools-playwright/pyproject.toml

...ama-index-tools-playwright/tests/test_tools_playwright.py