Cleanup: CMake: Modernize bf_windowmanager dependencies

Pretty straightforward

- Remove any windowmanager paths from INC
- Add a dependency though LIB when needed

context: https://devtalk.blender.org/t/cmake-cleanup/30260

Pull Request: https://projects.blender.org/blender/blender/pulls/109984

source/blender/python/intern/CMakeLists.txt

@@ -12,7 +12,6 @@ set(INC
   ../../imbuf
   ../../imbuf/intern/oiio
   ../../makesrna
-  ../../windowmanager
   ../../../../intern/clog
   ../../../../intern/mantaflow/extern
   ../../../../intern/opencolorio
@@ -130,6 +129,7 @@ set(LIB
 
   ${PYTHON_LINKFLAGS}
   ${PYTHON_LIBRARIES}
+  PRIVATE bf::windowmanager
 )
 
 # only to check if buildinfo is available