Fixed the bug that the first query may be rejected when read only in table model for simple consensus

(cherry picked from commit 95648df)

Author: Caideyipi

iotdb-core/consensus/src/main/java/org/apache/iotdb/consensus/ratis/RatisConsensus.java

@@ -324,6 +324,8 @@ public TSStatus write(ConsensusGroupId groupId, IConsensusRequest request)
     }
 
     // current Peer is group leader and in ReadOnly State
+    // We only judge dataRegions here, because schema write when readOnly is handled at
+    // RegionWriteExecutor
     if (isLeader(groupId) && Utils.rejectWrite(consensusGroupType)) {
       try {
         forceStepDownLeader(raftGroup);

iotdb-core/consensus/src/main/java/org/apache/iotdb/consensus/simple/SimpleConsensus.java

@@ -119,7 +119,8 @@ public TSStatus write(ConsensusGroupId groupId, IConsensusRequest request)
     SimpleConsensusServerImpl impl =
         Optional.ofNullable(stateMachineMap.get(groupId))
             .orElseThrow(() -> new ConsensusGroupNotExistException(groupId));
-    if (impl.isReadOnly()) {
+    // Schema Write when readOnly is handled at RegionWriteExecutor
+    if (impl.isReadOnly() && groupId instanceof DataRegionId) {
       return StatusUtils.getStatus(TSStatusCode.SYSTEM_READ_ONLY);
     } else {
       TSStatus status;

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/executor/RegionWriteExecutor.java

@@ -187,6 +187,8 @@ private class WritePlanNodeExecutionVisitor
     public RegionExecutionResult visitPlan(
         final PlanNode node, final WritePlanNodeExecutionContext context) {
 
+      // All the plans are rejected here when readOnly except for insertion, which is rejected in
+      // the stateMachine's "write" interface
       if (CommonDescriptor.getInstance().getConfig().isReadOnly() && !isForceExecutedPlan(node)) {
         return RegionExecutionResult.create(
             false,