rpc: Fix implicit-integer-sign-change in gettxout

Author: MacroFake

src/rpc/blockchain.cpp

@@ -993,8 +993,7 @@ static RPCHelpMan gettxout()
     UniValue ret(UniValue::VOBJ);
 
     uint256 hash(ParseHashV(request.params[0], "txid"));
-    int n = request.params[1].get_int();
-    COutPoint out(hash, n);
+    COutPoint out{hash, request.params[1].getInt<uint32_t>()};
     bool fMempool = true;
     if (!request.params[2].isNull())
         fMempool = request.params[2].get_bool();