Using null coalescing operator with fallback to 'false'
to avoid undefined array key access warnings when key
'casesensitiveComp' is not set. Using 'false' here as
this matches the behaviour of <PHP8.0, and as this is
used as method argument of type bool a bool typecase
is added along the way to be on the safe side.

Resolves: #96537
Releases: main, 11.5
Change-Id: I3c4df09b2adf5eec57e31947189f4a1e2aea4bd2