disableResize property of dialog is not serialized

[NitnerocL]

Hi, there is a bug with dialogs serialization where the property of being resizable or not is not resumed from saved state.

Repro steps

1. Go to https://node-projects.github.io/dock-spawn-ts/page/demo/ide/demo.html and refresh the layout
2. DockTreeVisualizer dialog is not resizable
3. Refresh the page
4. The layout is resumed but the dialog is now resizable

Expected behavior

Dialogs should keep their resizing behavior when restoring state.