Fix FabricTable memoryleak in DeviceControllerSystemState (#14658)

FabricTable is instantiated in DeviceControllerFactory::InitSystemState
as shown below

```
    stateParams.fabricTable           = chip::Platform::New<FabricTable>();
```

stateParams (type: DeviceControllerSystemStateParams) is then passed
onto DeviceControllerFactory::mSystemState (type: DeviceControllerSystemState), where stateParams.fabricTable is now stored in mSystemState.mFabrics.

We need to ensure that the original memory allocated in the initial step
is now freed in DeviceControllerSystemState::Shutdown()

src/controller/CHIPDeviceControllerFactory.cpp

@@ -284,6 +284,12 @@ CHIP_ERROR DeviceControllerSystemState::Shutdown()
         mSessionMgr = nullptr;
     }
 
+    if (mFabrics != nullptr)
+    {
+        chip::Platform::Delete(mFabrics);
+        mFabrics = nullptr;
+    }
+
     return CHIP_NO_ERROR;
 }