Tests/RunCMake/CXXModules: remove experimental settings

Logical conflicts between the topic that introduced the tests and the
removal of the experimental flag completely.

Tests/RunCMake/CXXModules/examples/export-include-directories-build/test/CMakeLists.txt

@@ -1,8 +1,6 @@
 cmake_minimum_required(VERSION 3.24)
 project(cxx_modules_library NONE)
 
-set(CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API "ac01f462-0f5f-432a-86aa-acef252918a6")
-
 find_package(export_include_directories REQUIRED)
 
 if (NOT TARGET CXXModules::export_include_directories)

Tests/RunCMake/CXXModules/examples/export-include-directories-install/test/CMakeLists.txt

@@ -1,8 +1,6 @@
 cmake_minimum_required(VERSION 3.24...3.28)
 project(cxx_modules_library NONE)
 
-set(CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API "ac01f462-0f5f-432a-86aa-acef252918a6")
-
 find_package(export_include_directories REQUIRED)
 
 if (NOT TARGET CXXModules::export_include_directories)