…ers and improving exception management

…nd normalizing test cases

…d updating filtering logic

… to _ConnectionStringAllowList

- Updated references in connection.py, connection_string_allowlist.py, connection_string_parser.py, and related test files to use the new class name.
- Changed method names from `parse` to `_parse` in _ConnectionStringParser for internal consistency.
- Adjusted unit tests to reflect the new class and method names, ensuring all tests pass with the updated structure.
- Improved code clarity and maintainability by adhering to naming conventions for internal classes.

…nd improve error handling for empty values

…ate test cases for parameter normalization

… include synonym and clarify usage

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

- Removed unused 'List' and 'logging' imports from connection_string_parser.py
- Removed unused 'sys', 'pooling', and 'threading' imports from test_003_connection.py
- Removed unused variables and unnecessary pass statements in tests
- Cleaned up test_012_connection_string_integration.py imports

All tests passing: 226 passed, 4 skipped

- Added type hints to _ConnectionStringParser.__init__()
- Added type hints to _get_reserved_parameters()

…ogic and improving parameter normalization