Fix deferred shadow init (#1900)

Fixed an issue where sometimes the deferred shadow texture would not be valid, causing wrong rendering.

com.unity.render-pipelines.high-definition/CHANGELOG.md

 
 ## [3.4.0-preview]
 
+### Fixed
+- Fixed an issue where sometimes the deferred shadow texture would not be valid, causing wrong rendering.
+
 ## [3.3.0-preview]
 
 ### Added

com.unity.render-pipelines.high-definition/HDRP/RenderPipeline/HDRenderPipeline.cs

                                 HDUtils.SetRenderTarget(cmd, hdCamera, m_ScreenSpaceShadowsBuffer, ClearFlag.Color, CoreUtils.clearColorAllBlack);
                             }
 
+                            // In some cases when loading a project for the first time in the editor, the internal resource is destroyed.
+                            // When used as render target, the C++ code will re-create the resource automatically. Since here it's used directly as an UAV, we need to check manually/
+                            if (!m_ScreenSpaceShadowsBuffer.rt.IsCreated())
+                                m_ScreenSpaceShadowsBuffer.rt.Create();
+
                             m_LightLoop.RenderScreenSpaceShadows(hdCamera, m_ScreenSpaceShadowsBuffer, GetDepthTexture(), cmd);
                             PushFullScreenDebugTexture(hdCamera, cmd, m_ScreenSpaceShadowsBuffer, FullScreenDebugMode.ScreenSpaceShadows);
                         }