search: Generalize parsing of predicate values

Created by: camdencheek

To support parameter values like contains(file:test), we had to add an exception to the parsing rules to continue parsing through parantheses in the case that we are parsing one of the reserved predicate keywords. This should be generalized to allow for multiple predicate names, and also re-thought to make sure this is the correct place to do this check.

Related to #18584 (closed)