[python][cmake] Temporary fix for includes currently depending on a specific order

!1124 (merged) reveals that the cmake Python modules currently require to be included in some specific order. Currently, when disabling the Python bindings we therefore get a warning that no virtual environment could be found. This is because the virtual environment script uses a Python interpreter but assumes that it has already been looked for.

This is a temporary fix after !1124 (merged). But I would suggest to clean this up more. Maybe after !1222 (merged) and !1096 (merged) have been merged.