update mStagingNetwork to the dataset in NVS after thread panid changed

src/platform/OpenThread/GenericNetworkCommissioningThreadDriver.cpp

@@ -47,6 +47,7 @@ CHIP_ERROR GenericThreadDriver::Init(Internal::BaseDriver::NetworkStatusChangeCa
 {
     ThreadStackMgrImpl().SetNetworkStatusChangeCallback(statusChangeCallback);
     ThreadStackMgrImpl().GetThreadProvision(mStagingNetwork);
+    ReturnErrorOnFailure(PlatformMgr().AddEventHandler(OnThreadStateChangeHandler, reinterpret_cast<intptr_t>(this)));
 
     // If the network configuration backup exists, it means that the device has been rebooted with
     // the fail-safe armed. Since OpenThread persists all operational dataset changes, the backup
@@ -56,6 +57,16 @@ CHIP_ERROR GenericThreadDriver::Init(Internal::BaseDriver::NetworkStatusChangeCa
     return CHIP_NO_ERROR;
 }
 
+void GenericThreadDriver::OnThreadStateChangeHandler(const ChipDeviceEvent * event, intptr_t arg)
+{
+    if ((event->Type == DeviceEventType::kThreadStateChange) &&
+        (event->ThreadStateChange.OpenThread.Flags & OT_CHANGED_THREAD_PANID))
+    {
+        // Update the mStagingNetwork when thread panid changed
+        ThreadStackMgrImpl().GetThreadProvision(reinterpret_cast<GenericThreadDriver *>(arg)->mStagingNetwork);
+    }
+}
+
 void GenericThreadDriver::Shutdown()
 {
     ThreadStackMgrImpl().SetNetworkStatusChangeCallback(nullptr);

src/platform/OpenThread/GenericNetworkCommissioningThreadDriver.h

@@ -116,6 +116,7 @@ class GenericThreadDriver final : public ThreadDriver
 private:
     uint8_t scanNetworkTimeoutSeconds;
     uint8_t connectNetworkTimeout;
+    static void OnThreadStateChangeHandler(const ChipDeviceEvent * event, intptr_t arg);
     Status MatchesNetworkId(const Thread::OperationalDataset & dataset, const ByteSpan & networkId) const;
     CHIP_ERROR BackupConfiguration();