[web-components]: update tests for all components

[kennylam]

Unit tests for all components should be updated to match those in @carbon/react. While elements and names will certainly have differences, test assertions and expectations should match as closely as possible.

New/refactored tests should first be done for components which have already been synced with their React counterpart, see #17992.

See open-wc/testing for more information on the testing API and #18780 as an example.