Executable model - kcontext cannot be used as a RuleContext

When using kcontext in RHS as a RuleContext, the execution throws incompatible types exception [1]. The problem could be that kcontext is translated to Drools and not to DroolsImpl in the model DSLs.

PR with a reproducer is here: https://github.com/kiegroup/drools/pull/1896/files#diff-67291fa531041ec60d75478a86b936e9R103

[1] https://gist.github.com/baldimir/94cd43fc10215dd3ef8dad16a0e830d8