9.9.0-rc.6

Compared to 9.9.0-rc.5+e17ce5c6 (from !573 (merged)), this version contains these fixes/changes:

• #329 (closed) (fixed by !577 (merged)) Break conditions dropdown: When nothing is selected the dropdown is empty (instead of "None") and the tooltip is empty
• #323 (closed) (fixed by !566 (merged)) Lock test plan: Parameter features are not locked
• #328 (closed) (fixed by !576 (merged)) Break conditions: No break message in log when execution stops on the highest hierarchy