Workaround unity_StereoEyeIndex issue with stereo instancing

Basically, something is going wrong with UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX or stereoTargetEyeIndex in stereo instancing. We can work around it by not calling it, because UNITY_SETUP_INSTANCE_ID sets up unity_StereoEyeIndex for us, if instancing is enabled.

ScriptableRenderPipeline/LightweightPipeline/LWRP/Shaders/LightweightScreenSpaceShadows.shader

         SAMPLER(sampler_CameraDepthTexture);
 #endif
 
-        struct VertexInput
-        {
-            float4 vertex   : POSITION;
-            float2 texcoord : TEXCOORD0;
-            UNITY_VERTEX_INPUT_INSTANCE_ID
-        };
-
         struct FullScreenInput
         {
             uint vertexID : SV_VertexID;
             UNITY_VERTEX_OUTPUT_STEREO
         };
 
-        //Interpolators Vertex(VertexInput i)
         Interpolators Vertex(FullScreenInput i)
         {
             Interpolators o;
 
-            //o.pos = TransformObjectToHClip(i.vertex.xyz);
-            //o.texcoord.xy = i.texcoord;
-            //o.texcoord.xy = UnityStereoTransformScreenSpaceTex(i.texcoord.xy);
             o.texcoord.xy = GetFullScreenTriangleTexCoord(i.vertexID);
             o.texcoord.zw = projPos.xy;
 
         half Fragment(Interpolators i) : SV_Target
         {
             UNITY_SETUP_INSTANCE_ID(i);
+#if !defined(UNITY_STEREO_INSTANCING_ENABLED) 
+            // Completely unclear why i.stereoTargetEyeIndex doesn't work here, considering  
+            // this has to be correct in order for the texture array slices to be rasterized to 
+            // We can limit this workaround to stereo instancing for now. 
+#endif
-            // Completely unclear why i.stereoTargetEyeIndex doesn't work here, considering
-            // this has to be correct in order for the texture array slices to be rasterized to
-            unity_StereoEyeIndex = i.instanceID;
             float deviceDepth = SAMPLE_TEXTURE2D_ARRAY(_CameraDepthTexture, sampler_CameraDepthTexture, adjTexCoords, unity_StereoEyeIndex).r;
 #else
             float deviceDepth = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, sampler_CameraDepthTexture, adjTexCoords);