[mac] fix channel switching issue during energy scan (#9405)

- This commit resolves inconsistency between Host and RCP channel on
  scan energy when network not created.
- Added fix in MAC layer to update the channel on scan energy.

src/core/mac/mac.cpp

@@ -340,6 +340,10 @@ void Mac::PerformEnergyScan(void)
     }
     else
     {
+        if (!GetRxOnWhenIdle())
+        {
+            mLinks.Receive(mScanChannel);
+        }
         error = mLinks.EnergyScan(mScanChannel, mScanDuration);
     }