Add the use of the qt_internal_project_setup function

The function sets the required CMake variables and policies.

Pick-to: 6.5
Task-number: QTBUG-112685
Change-Id: Icf3d63847085b11e2453978f0dc51b968847c5bb
Reviewed-by: Amir Masoud Abdol <amir.abdol@qt.io>

CMakeLists.txt

@@ -13,6 +13,8 @@ project(QtImageFormats
 
 find_package(Qt6 ${PROJECT_VERSION} CONFIG REQUIRED COMPONENTS BuildInternals Core)
 find_package(Qt6 ${PROJECT_VERSION} QUIET CONFIG OPTIONAL_COMPONENTS Gui)
+qt_internal_project_setup()
+
 if(NOT TARGET Qt::Gui)
     message(NOTICE "Skipping the build as the condition \"TARGET Qt::Gui\" is not met.")
     return()