IWYU: Update for Debian 12 CI job

`include-what-you-use` diagnostics, in practice, are specific to
the environment's compiler and standard library.  Update includes
to satisfy IWYU for our CI job under Debian 12.

Source/cmInstallScriptGenerator.h

@@ -9,7 +9,6 @@
 
 #include "cmInstallGenerator.h"
 #include "cmListFileCache.h"
-#include "cmScriptGenerator.h"
 
 class cmLocalGenerator;