See if we can simply `listFormulaIsEmpty()` with introduction of `undef`

[lochana-chathura]

Description:
With the introduction of undef type to the type engine, we were able to simplify the mappingFormulaIsEmpty() logic and make it aligned with the algorithm in exercise 10 of the Cov-Contra paper. Changes are made with PR #1175.

Similarly, see if we can achieve the same with listFormulaIsEmpty().