rpc/wallet: use OMITTED_NAMED_ARG instead of Default(VNULL)

Author: kallewoof

src/wallet/rpcwallet.cpp

@@ -2568,7 +2568,7 @@ static RPCHelpMan loadwallet()
                 "\napplied to the new wallet (eg -rescan, etc).\n",
                 {
                     {"filename", RPCArg::Type::STR, RPCArg::Optional::NO, "The wallet directory or .dat file."},
-                    {"load_on_startup", RPCArg::Type::BOOL, RPCArg::Default{UniValue::VNULL}, "Save wallet name to persistent settings and load on startup. True to add wallet to startup list, false to remove, null to leave unchanged."},
+                    {"load_on_startup", RPCArg::Type::BOOL, RPCArg::Optional::OMITTED_NAMED_ARG, "Save wallet name to persistent settings and load on startup. True to add wallet to startup list, false to remove, null to leave unchanged."},
                 },
                 RPCResult{
                     RPCResult::Type::OBJ, "", "",
@@ -2699,7 +2699,7 @@ static RPCHelpMan createwallet()
             {"passphrase", RPCArg::Type::STR, RPCArg::Optional::OMITTED_NAMED_ARG, "Encrypt the wallet with this passphrase."},
             {"avoid_reuse", RPCArg::Type::BOOL, RPCArg::Default{false}, "Keep track of coin reuse, and treat dirty and clean coins differently with privacy considerations in mind."},
             {"descriptors", RPCArg::Type::BOOL, RPCArg::Default{false}, "Create a native descriptor wallet. The wallet will use descriptors internally to handle address creation"},
-            {"load_on_startup", RPCArg::Type::BOOL, RPCArg::Default{UniValue::VNULL}, "Save wallet name to persistent settings and load on startup. True to add wallet to startup list, false to remove, null to leave unchanged."},
+            {"load_on_startup", RPCArg::Type::BOOL, RPCArg::Optional::OMITTED_NAMED_ARG, "Save wallet name to persistent settings and load on startup. True to add wallet to startup list, false to remove, null to leave unchanged."},
             {"external_signer", RPCArg::Type::BOOL, RPCArg::Default{false}, "Use an external signer such as a hardware wallet. Requires -signer to be configured. Wallet creation will fail if keys cannot be fetched. Requires disable_private_keys and descriptors set to true."},
         },
         RPCResult{
@@ -2790,7 +2790,7 @@ static RPCHelpMan unloadwallet()
                 "Specifying the wallet name on a wallet endpoint is invalid.",
                 {
                     {"wallet_name", RPCArg::Type::STR, RPCArg::DefaultHint{"the wallet name from the RPC endpoint"}, "The name of the wallet to unload. If provided both here and in the RPC endpoint, the two must be identical."},
-                    {"load_on_startup", RPCArg::Type::BOOL, RPCArg::Default{UniValue::VNULL}, "Save wallet name to persistent settings and load on startup. True to add wallet to startup list, false to remove, null to leave unchanged."},
+                    {"load_on_startup", RPCArg::Type::BOOL, RPCArg::Optional::OMITTED_NAMED_ARG, "Save wallet name to persistent settings and load on startup. True to add wallet to startup list, false to remove, null to leave unchanged."},
                 },
                 RPCResult{RPCResult::Type::OBJ, "", "", {
                     {RPCResult::Type::STR, "warning", "Warning message if wallet was not unloaded cleanly."},