Added support for dereferenced map properties (#2635)

* Added support for dereferenced properties

* Added negative test

* Update pkg/exprparser/functions_test.go

Co-authored-by: ChristopherHX <christopher.homberger@web.de>

* Update pkg/exprparser/functions_test.go

Co-authored-by: ChristopherHX <christopher.homberger@web.de>

* fix lint

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Co-authored-by: m1r4c <lars-github@domesjo.com>
Co-authored-by: ChristopherHX <christopher.homberger@web.de>