chore(SecureMemoryAllocator): include optional header

* Add `<optional>` header for improved type handling
* Enhances memory allocation functionality

Author: saturneric

src/core/function/SecureMemoryAllocator.cpp

@@ -37,6 +37,7 @@
 #include <algorithm>
 #include <cstdlib>
 #include <cstring>
+#include <optional>
 
 namespace GpgFrontend {
 class SecureMemoryAllocator;