setFilterRegExp retains the caseSensitivity() while setFilterRegularExpression did not.
Change setFilterRegularExpression to also retain the case sensitivity.
Fixes: QTBUG-83313
Pick-to: 5.15
Change-Id: I46f494d320aee99d50612f01f63558c693276989
Reviewed-by: Samuel Gaist <samuel.gaist@idiap.ch>
Reviewed-by: David Faure <david.faure@kdab.com>