Fix windowing crashes

[Doprez]

PR Details

There were 2 different issues here. One was an issue with the OnToggle event causing the switch from fullscreen to windowed to be reset to true within the same call causing an exception.

The other issue was with the exit game call trying to recreate a disposed graphics device in the GameBase class.

Related Issue

https://github.com/stride3d/stride/issues/2008 https://github.com/stride3d/stride/issues/1493

Motivation and Context

Window changes shouldnt cause a crash.

Types of changes

• [ ] Docs change / refactoring / dependency upgrade
• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• [ ] My change requires a change to the documentation.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.
• [x] I have built and run the editor to try this change out.