Revise fix for doctests

[timlinux]

Description

After making #9152
I since chatted with@elpaso and the fixes that replace the expected returns are not good. In particular, returning strings for enums is what should be happening so instead of just checking the enums as numbers, we need to go back and figure out the underlying reason why the enum strings are not being returned.

Also the problem reported e.g. here hasn't been resolved:

#8 [3/4] RUN pip3 install -r /documentation/REQUIREMENTS.txt
#8 0.447 error: externally-managed-environment
#8 0.447 
#8 0.447 × This environment is externally managed
#8 0.447 ╰─> To install Python packages system-wide, try apt install
#8 0.447     python3-xyz, where xyz is the package you are trying to
#8 0.447     install.

The proper fix will be to not try to install packages globally using pip, but to rather make a venv and install them there.