cmake: use WEST_PYTHON as a preferred python installation if defined.

Fixes: #34368

Now added WEST_PYTHON to list of preferred pythons to check.
WEST_PYTHON is added after PYTHON_PREFER so that a user may still
request a specific python is used by supplying
`-DPYTHON_PREFER=<python>` even when building using `west build`.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
1 file changed