Added Case-Insensitive Functions for Coalesce, IfNull, and NullIf

Why it matters

The feature solves the issue of performing null handling operations in a case-insensitive manner, allowing users to compare and handle string values without case sensitivity affecting the outcome. This enhances flexibility and accuracy when working with textual data that may vary in letter casing.

How to use it

Users can apply the new case-insensitive functions by using the newly added variants of coalesce, ifNull, and nullIf designed to ignore case differences in string comparisons. Refer to the function documentation for syntax and examples.