If current control (for example TabPageContainer) is missing
resource listener property we should not fail script with
exception. Just behave as with empty ResourceListener.

Change-Id: I260feec775a5d197bebc9414b652dd6f89e35035
Reviewed-on: https://gerrit.libreoffice.org/69740
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>