SAK-50613 Samigo issue with calculated questions using the pipe and comma operators

[st-manu]

https://sakaiproject.atlassian.net/browse/SAK-50613

The formulas for calculated questions are stored in the database by concatenating the formula with "|tol,dec". This causes two issues:

1. The "|" symbol is also used as the OR operator.
2. The comma is not only used as a decimal separator but is also used in formulas (such as if) to separate arguments.

When a formula is configured, for example, as: iff({numero}<2, {sub}|{numero}, {numero}=2, {sub}*3, {numero}>2, {sub}*6), the question breaks.

[ern]

@st-manu can you add a unit test for this?

[st-manu]

I have uploaded a new commit with the tests @ern