Refactor: Every stacked toast renders with the same data-testid="error-tooltip" and testId="error-tooltip-close". With multiple warnings visible (which is the entire point of this refactor), getByTestId queries become ambiguous and existing e2e/unit tests that target these IDs will break or match a single one non-deterministically.

Refactor: Every stacked toast renders with the same data-testid="error-tooltip" and testId="error-tooltip-close". With multiple warnings visible (which is the entire point of this refactor), getByTestId queries become ambiguous and existing e2e/unit tests that target these IDs will break or match a single one non-deterministically. #78