refactor(tests): enhance global token tests and remove scrollbar mixin tests

- Updated global token tests to include snapshot testing for the globalThemeToken object.
- Modified checks for transparent color variables to account for var() references.
- Removed scrollbar and scrollbarHidden mixin tests to streamline the test suite.
- Improved variable naming convention tests to support camelCase.
- Added snapshot tests for theme object structure and ensured all values are valid CSS variable formats.
- Simplified theme object tests by focusing on essential properties and their formats.

Author: chenshuai2144