Fix CMake Deprecation Warning: "CMakeFindFrameworks.cmake is not maintained"

[bennettgoble]

Description

CMakeFindFrameworks has been deprecated since CMake 3.31. We need to replace it with find_library before CMake removes it.

Recent build snippet:

CMake Warning (dev) at /opt/homebrew/share/cmake/Modules/CMakeFindFrameworks.cmake:29 (message):
  CMakeFindFrameworks.cmake is not maintained and lacks support for more
  recent framework handling.  It will be removed in a future version of
  CMake.  Update the code to use find_library() instead.
Call Stack (most recent call first):
  cmake/Linking.cmake:70 (include)
  cmake/APR.cmake:1 (include)
  cmake/LLCommon.cmake:3 (include)
  llmessage/CMakeLists.txt:7 (include)