[Graphics] Fix resource memory leak

[Eideren]

PR Details

It's unlikely that resources were ever manually released given that objects that hold and uses those buffers do not implement IDisposable, they are expected to be GC'ed not explicitly 'destroyed'. The device's resources are now weakly referenced and native stuff is cleaned up when resource are GC'ed, through their destructor.

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.
• [x] All new and existing tests passed.