* 🖥️ feat: Add Proxy Support for Tavily API Tool
- Integrated ProxyAgent from undici to enable proxy support for API requests in TavilySearch and TavilySearchResults.
- Updated fetch options to conditionally include the proxy configuration based on the environment variable, enhancing flexibility for network requests.
* ci: TavilySearchResults with Proxy Support Tests
- Added tests to verify the integration of ProxyAgent for API requests in TavilySearchResults.
- Implemented conditional logic to check for the PROXY environment variable, ensuring correct usage of ProxyAgent based on its presence.
- Updated test setup to clear mocks before each test for improved isolation and reliability.
* fix: get user-provided API key using environment variable names as keys
* feat: Add error handling for missing API key and search engine ID
* feat: Add GoogleSearch and TavilySearchResults specs for environment variables handling
---------
Co-authored-by: Dongwoo Jeong <dongwoo.jeong@lge.com>
