Feature: #100586 - Null-safe operator in TypoScript conditions

See forge#100586

Description

By raising TYPO3's Symfony dependencies to 6.2 in forge#99239, a couple of new features were made available for the expression language, which is used by TYPO3 for its TypoScript conditions.

One of those new features is the null-safe operator. This operator is especially useful when accessing properties on objects, which however might not be available in some context, e.g. "TSFE" in the backend.

TYPO3 designed its custom expression functions in a way that they support the usage of the null-safe operator by default. This is done by returning NULL in case the requested object is not available.

Therefore, instead of [getTSFE() && getTSFE().id == 123], integrators can simplify the condition to [getTSFE()?.id == 123].

Impact

It's now possible to simplify TypoScript conditions using the new expression language features, especially the null-safe operator.