[6000][UUM-67306] Fix macOS flickering for 2D Renderer

Fix flickering for 2D Renderer on macOS silicon

Author: kennytann

Packages/com.unity.render-pipelines.universal/Runtime/2D/Passes/Utility/RendererLighting.cs

@@ -578,7 +578,7 @@ internal static void RenderNormals(this IRenderPass2D pass, ScriptableRenderCont
                 var msaaEnabled = renderingData.cameraData.cameraTargetDescriptor.msaaSamples > 1;
                 var storeAction = msaaEnabled ? RenderBufferStoreAction.Resolve : RenderBufferStoreAction.Store;
                 var clearFlag = pass.rendererData.useDepthStencilBuffer ? ClearFlag.All : ClearFlag.Color;
-                clearFlag = bFirstClear ? clearFlag : ClearFlag.None;
+                clearFlag = bFirstClear ? clearFlag : ClearFlag.Color;
                 bFirstClear = false;
 
                 if (depthTarget != null)