DMN FEEL custom Frame is always initialized

ExecutionFrameImpl frame = new ExecutionFrameImpl(null);
this line in FEELImpl is present even when no profile, hence the was-Optional is always populated.

Fix initialization, see diff for old code reference:
https://github.com/kiegroup/drools/pull/2341/files#diff-b99bdc7c33feee36a7ef664061aa6908L77