[fix](paimon) add rest external catalog for gson comaptiblity (apache#60916)

Some user from old version will create and persist
PaimonRestExternalCatalog instance.

Author: morningman

fe/fe-core/src/main/java/org/apache/doris/datasource/paimon/PaimonRestExternalCatalog.java

@@ -0,0 +1,29 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.apache.doris.datasource.paimon;
+
+import java.util.Map;
+
+@Deprecated
+public class PaimonRestExternalCatalog extends PaimonExternalCatalog {
+
+    public PaimonRestExternalCatalog(long catalogId, String name, String resource,
+            Map<String, String> props, String comment) {
+        super(catalogId, name, resource, props, comment);
+    }
+}

fe/fe-core/src/main/java/org/apache/doris/persist/gson/GsonUtils.java

@@ -169,6 +169,7 @@
 import org.apache.doris.datasource.paimon.PaimonExternalTable;
 import org.apache.doris.datasource.paimon.PaimonFileExternalCatalog;
 import org.apache.doris.datasource.paimon.PaimonHMSExternalCatalog;
+import org.apache.doris.datasource.paimon.PaimonRestExternalCatalog;
 import org.apache.doris.datasource.test.TestExternalCatalog;
 import org.apache.doris.datasource.test.TestExternalDatabase;
 import org.apache.doris.datasource.test.TestExternalTable;
@@ -420,6 +421,7 @@ public class GsonUtils {
                 .registerSubtype(PaimonExternalCatalog.class, PaimonExternalCatalog.class.getSimpleName())
                 .registerSubtype(PaimonHMSExternalCatalog.class, PaimonHMSExternalCatalog.class.getSimpleName())
                 .registerSubtype(PaimonFileExternalCatalog.class, PaimonFileExternalCatalog.class.getSimpleName())
+                .registerSubtype(PaimonRestExternalCatalog.class, PaimonRestExternalCatalog.class.getSimpleName())
                 .registerSubtype(MaxComputeExternalCatalog.class, MaxComputeExternalCatalog.class.getSimpleName())
                 .registerSubtype(
                             TrinoConnectorExternalCatalog.class, TrinoConnectorExternalCatalog.class.getSimpleName())