Add imgui_test_engine include path to CMake configuration

- Updated CMake files for both emu and z3ed to include the imgui_test_engine directory in the target include directories.
- This change ensures that the necessary headers for the imgui_test_engine are accessible during the build process, facilitating UI testing capabilities.

src/cli/z3ed.cmake

@@ -40,6 +40,7 @@ target_include_directories(
   ${CMAKE_SOURCE_DIR}/src/lib/asar/src/asar-dll-bindings/c
   ${CMAKE_SOURCE_DIR}/incl/
   ${CMAKE_SOURCE_DIR}/src/
+  ${CMAKE_SOURCE_DIR}/src/lib/imgui_test_engine
   ${PNG_INCLUDE_DIRS}
   ${SDL2_INCLUDE_DIR}
   ${GLEW_INCLUDE_DIRS}