Cutter doesn't preserve Graph Layout after reset

Environment information

• Operating System: Any
• Cutter version: latest - master
• File format: Any

Describe the bug

There are actually two related bugs:

1. When changing the graph layout to another layout and restarting Cutter. The graph layout is back to its default value. Cutter should preserve the user's preferences.
2. After changing the graph layout and clicking "Reset Settings", the layout stays changed until Cutter is re-opened. I'd expect the layout to be reset to its default layout when resetting settings and don't wait for the restart to take effect.

To Reproduce

Scenario 1: 0. Open a binary in Cutter

1. Open the Graph widget
2. Right-click on the graph, and select a layout from the Layout context item. e.g "Graphviz polyline LR"
3. Exit Cutter
4. Re-open Cutter and go to the graph widget
5. See that the graph returned to its default layout

Scenario 2: 0. Open a binary in Cutter

1. Open the Graph widget
2. Right-click on the graph, and select a layout from the Layout context item. e.g "Graphviz polyline LR"
3. See that the graph layout has changed
4. Now select "View -> Reset Settings" from the main toolbar
5. Inspect that the graph did not change to its default layout
6. Restart Cutter and open a binary. See that the layout returned to default Steps to reproduce the behavior:
7. Go to '...'
8. Click on '....'
9. Scroll down to '....'
10. See error

Expected behavior

The chosen layout should be saved in Settings, preserved in each execute of Cutter, and return to its Default layout when the settings are reset.