Merge pull request swiftlang#71565 from compnerd/sddl

Windows: include SDDL conversion headers

Author: compnerd

stdlib/public/Platform/winsdk.modulemap

@@ -315,6 +315,8 @@ module WinSDK [system] {
   }
 
   module Security {
+    header "../shared/sddl.h"
+
     module AuthZ {
       header "AuthZ.h"
       export *