Fixed the configMTree deserialisation bug for "root" database (#16961)

Author: Caideyipi

iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/persistence/schema/ConfigMTree.java

@@ -1109,15 +1109,13 @@ public void deserialize(final InputStream inputStream) throws IOException {
       name = tableNode.getName();
       stack.push(new Pair<>(tableNode, false));
     } else {
-      // Currently internal mNode will not be the leaf node and thus will not be deserialized here
-      // This is just in case
       internalMNode = deserializeInternalMNode(inputStream);
       ReadWriteIOUtils.readInt(inputStream);
       name = internalMNode.getName();
       stack.push(new Pair<>(internalMNode, false));
     }
 
-    while (!PATH_ROOT.equals(name)) {
+    while (!PATH_ROOT.equals(name) || type != INTERNAL_MNODE_TYPE) {
       type = ReadWriteIOUtils.readByte(inputStream);
       switch (type) {
         case INTERNAL_MNODE_TYPE:

iotdb-core/confignode/src/test/java/org/apache/iotdb/confignode/persistence/schema/ConfigMTreeTest.java

@@ -261,7 +261,7 @@ public void testGetNodeListInLevel() throws MetadataException {
   public void testSerialization() throws Exception {
     final PartialPath[] pathList =
         new PartialPath[] {
-          new PartialPath("root.sg"),
+          new PartialPath("root.`root`"),
           new PartialPath("root.a.sg"),
           new PartialPath("root.a.b.sg"),
           new PartialPath("root.a.a.b.sg")