[Core] Fix XR support in CoreUtils.Drawfullscreen (#6287)

* Fix XR support in CoreUtils.DrawFullscreen function

* Updated changelog

Co-authored-by: sebastienlagarde <[email protected]>

Author: Antoine Lelievre

com.unity.render-pipelines.core/CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Fixed
 - Fixed potentially conflicting runtime Rendering Debugger UI command by adding an option to disable runtime UI altogether (1345783).
 - Fixed issue when changing volume profiles at runtime with a script (case 1364256).
+- Fixed XR support in CoreUtils.DrawFullscreen function.
 
 ## [10.7.0] - 2021-07-02
 

com.unity.render-pipelines.core/Runtime/Utilities/CoreUtils.cs

@@ -725,7 +725,7 @@ public static void DrawFullScreen(CommandBuffer commandBuffer, Material material
             RenderTargetIdentifier colorBuffer,
             MaterialPropertyBlock properties = null, int shaderPassId = 0)
         {
-            commandBuffer.SetRenderTarget(colorBuffer);
+            commandBuffer.SetRenderTarget(colorBuffer, 0, CubemapFace.Unknown, -1);
             commandBuffer.DrawProcedural(Matrix4x4.identity, material, shaderPassId, MeshTopology.Triangles, 3, 1, properties);
         }