23.x Add missing includes to fix gcc-13 compile error

Additional include fixes are required to make the 23.x branch compile
using GCC 13.

src/util/bip32.h

@@ -6,6 +6,7 @@
 #define BITCOIN_UTIL_BIP32_H
 
 #include <attributes.h>
+#include <cstdint>
 #include <string>
 #include <vector>
 

src/util/string.h

@@ -9,6 +9,7 @@
 
 #include <algorithm>
 #include <array>
+#include <cstdint>
 #include <cstring>
 #include <locale>
 #include <sstream>