[Python][CI] Remove use of CMAKE_POLICY_VERSION_MINIMUM on musllinux

### Describe the enhancement requested

When adding support for Python 3.14 the musllinux wheels started failing due to

```
#14 16.69 CMake Error at /opt/vcpkg/buildtrees/_vcpkg/build/_deps/cmakerc-src/CMakeRC.cmake:37 (cmake_minimum_required):
#14 16.69 Compatibility with CMake < 3.5 has been removed from CMake.
#14 16.69
#14 16.69 Update the VERSION argument value. Or, use the ... syntax
#14 16.69 to tell CMake that the project requires at least but has been updated
#14 16.69 to work with policies introduced by or earlier.
#14 16.69
#14 16.69 Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.
```

see: https://github.com/apache/arrow/pull/47616#step:7:329

Specifying `CMAKE_POLICY_VERSION_MINIMUM` helped, as per https://github.com/apache/arrow/pull/47616#issuecomment-3387347510. In the future it would be better if we can remove the use of it, see https://github.com/apache/arrow/pull/47616#discussion_r2426139055.

### Component(s)

Continuous Integration, Python