Fix RHI unit test failures and OpenGL backend issues

- Fix D3D12Texture::GetTextureType() to return correct type based on D3D12 resource dimension
- Fix OpenGL CommandQueue::Signal() to properly call fence->Signal()
- Fix OpenGL CommandQueue::GetTimestampFrequency() using GL_TIMESTAMP
- Fix OpenGL Device::GetNativeDevice() to return m_hglrc
- Fix OpenGL Fence::Signal() to create GL sync object and update completedValue
- Fix OpenGL Fence::Wait() to properly wait for fence
- Fix OpenGL Fence::GetNativeHandle() to create sync on first call
- Fix OpenGL SwapChain::GetCurrentBackBuffer() to return backbuffer texture
- Fix OpenGL SwapChain::Initialize() to create backbuffer texture
- Fix OpenGL SwapChain::Shutdown() to cleanup backbuffer texture
- Fix RHI unit tests: add missing sampleCount/sampleQuality/depth/arraySize fields
- Fix RHI unit tests: add complete TextureDesc fields where needed

engine/src/RHI/OpenGL/OpenGLDevice.cpp

@@ -450,7 +450,7 @@ const RHIDeviceInfo& OpenGLDevice::GetDeviceInfo() const {
 }
 
 void* OpenGLDevice::GetNativeDevice() {
-    return nullptr;
+    return m_hglrc;
 }
 
 void* OpenGLDevice::GetNativeHandle() const {