interfaces: Add helper function for wallet on pruning

src/node/interfaces.cpp

@@ -46,6 +46,7 @@
 #include <policy/settings.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
+#include <rpc/blockchain.h>
 #include <rpc/protocol.h>
 #include <rpc/server.h>
 #include <support/allocators/secure.h>
@@ -770,6 +771,11 @@ public:
         LOCK(::cs_main);
         return chainman().m_blockman.m_have_pruned;
     }
+    std::optional<int> getPruneHeight() override
+    {
+        LOCK(chainman().GetMutex());
+        return GetPruneHeight(chainman().m_blockman, chainman().ActiveChain());
+    }
     bool isReadyToBroadcast() override { return !chainman().m_blockman.LoadingBlocks() && !isInitialBlockDownload(); }
     bool isInitialBlockDownload() override
     {