executable model fails to handle property reactive with null-safe-dereferencing

[tkobayas]

When using null-safe-dereferencing !., exec-model fails to handle property reactive, so works like class reactive.

rule R 
when
    $p: Person(address!.street == "street1")
then
    modify($p) { setLikes("Cheese") };
end

This rule causes a loop.

[tkobayas]

Workaround:
Change (address!.street == "street1") to (address != null, address.street == "street1")

Note:
Ensure that ExpressionTyperContext.addReactOnProperties for the prop is called in https://github.com/apache/incubator-kie-drools/blob/main/drools-model/drools-model-codegen/src/main/java/org/drools/model/codegen/execmodel/generator/visitor/pattern/ClassPatternDSL.java#L276-L280

[tkobayas]

Fixed by #5963