Fix issue when using redux and checkIntervalOfflineOnly

[usrbowe]

What this PR fixes

If using redux integration and option checkIntervalOfflineOnly.
It will never make request to check internet connection.
HOC withNetworkConnectivity has internal state, in which connection status is stored.
This however never gets updated. It's only set once during initialisation.

Test scenario

Make sure there is no internet connection

withNetworkConnectivity({
  withRedux: true,
  checkConnectionInterval: 3000,
  checkIntervalOfflineOnly: true,
}),

Open app and check if there is any network request made to google.com. There will be no requests made. If we turn off option checkIntervalOfflineOnly, everything works fine.
With my change, it will always sync internal state with external redux state.

[rgommezz]

Thanks very much for this, great catch! Just some stylistic nits before merging.

[rgommezz]

Could you please destructure the store to avoid that long property access?

const { store } = this.context;
if (withRedux && store) {
	isConnected = store.getState().network.isConnected;
}

...

Also, could you also rephrase the comment to "When using redux integration, the connection state is coming from the store"

Thanks!

[usrbowe]

Yep, make sense 👍

[rgommezz]

Thanks very much @usrbowe!