[StatementSwitchToExpressionSwitch] for return switch pattern, if the switch has a default: clause and is otherwise exhaustive (even without said default: clause), then propose an alternative fix which removes the default: clause and its code.

[StatementSwitchToExpressionSwitch] for return switch pattern, if the switch has a default: clause and is otherwise exhaustive (even without said default: clause), then propose an alternative fix which removes the default: clause and its code. #7197