build: Fix GCC 14 compilation (#7981)

Co-authored-by: Ayaz Salikhov <mathbunnyru@users.noreply.github.com>

include/xrpl/json/json_value.h

@@ -4,6 +4,7 @@
 #include <xrpl/json/json_forwards.h>
 
 #include <cstring>
+#include <iterator>
 #include <limits>
 #include <map>
 #include <string>
@@ -524,6 +525,7 @@ public:
 class ValueIteratorBase
 {
 public:
+    using iterator_category = std::bidirectional_iterator_tag;
     using size_t = unsigned int;
     using difference_type = int;
     using SelfType = ValueIteratorBase;

src/xrpld/rpc/detail/RPCLedgerHelpers.cpp

@@ -331,6 +331,13 @@ getLedger<>(std::shared_ptr<ReadView const>&, LedgerShortcut shortcut, Context c
 template Status
 getLedger<>(std::shared_ptr<ReadView const>&, uint256 const&, Context const&);
 
+// explicit instantiation of ledgerFromSpecifier
+template Status
+ledgerFromSpecifier<>(
+    std::shared_ptr<ReadView const>&,
+    org::xrpl::rpc::v1::LedgerSpecifier const&,
+    Context const&);
+
 // The previous version of the lookupLedger command would accept the
 // "ledger_index" argument as a string and silently treat it as a request to
 // return the current ledger which, while not strictly wrong, could cause a lot