Add background polling to Device page to ensure correct editor access status is shown

### Description

ref https://github.com/flowforge/flowforge/issues/2439

When the Device Editor is enabled, the Device page shows this status. If the tunnel timesout in the background, the editor is no longer available. However the Device page doesn't know this and still shows it is enabled. This can cause confusion as the 'Open Editor' button will no longer work.

The proposal here is to add background polling of the device state to the page to ensure, if the tunnel gets closed, the page updates to reflect this.

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate