cmake: fix python version comparison due to whitespace

[katrinafyi]

Previously, there were warnings such as:

CMake Warning at CMakeLists.txt:131 (message):
  /usr/bin/python3.11 --version is 3.11.7

  , which is less then the minimum required, 3.5.2; disabling building of
  API.

The presence of whitespace turns VERSION_LESS into a lexicographic comparison, so python versions >=3.10 incorrectly compare less.

This change should fix this.

(using cmake 3.28.1)