Ensure _DecalLayerMaskFromDecal is allocated with enough size for instancing

This PR fixes an issue where the following error was being spawned on the console when enabling the instancing property of a *Decal* `Material` at runtime:

```"Property (_DecalLayerMaskFromDecal) exceeds previous array size (250 vs 1). Cap to previous size. Restart Unity to recreate the arrays."```

This happened because this `MaterialPropertyBlock` property only gets reallocated at domain-reload, which creates an issue when passing from regular drawing (size `1`) to instanced drawing (size `250`) at runtime.

Author: amsXYZ

Packages/com.unity.render-pipelines.universal/Runtime/Decal/Entities/DecalCreateDrawCallSystem.cs

@@ -207,7 +207,7 @@ public void Execute()
                     instanceIndex++;
 
                     int instanceCount = instanceIndex - instanceStart;
-                    bool isReachedMaximumBatchSize = instanceCount >= 250;
+                    bool isReachedMaximumBatchSize = instanceCount >= DecalDrawSystem.MaxBatchSize;
                     if (isReachedMaximumBatchSize)
                     {
                         subCalls[subCallIndex++] = new DecalSubDrawCall()

Packages/com.unity.render-pipelines.universal/Runtime/Decal/Entities/DecalDrawSystem.cs

@@ -9,6 +9,8 @@ namespace UnityEngine.Rendering.Universal
     /// </summary>
     internal abstract class DecalDrawSystem
     {
+        readonly static internal uint MaxBatchSize = 250;
+
         protected DecalEntityManager m_EntityManager;
         private Matrix4x4[] m_WorldToDecals;
         private Matrix4x4[] m_NormalToDecals;
@@ -21,9 +23,9 @@ public DecalDrawSystem(string sampler, DecalEntityManager entityManager)
         {
             m_EntityManager = entityManager;
 
-            m_WorldToDecals = new Matrix4x4[250];
-            m_NormalToDecals = new Matrix4x4[250];
-            m_DecalLayerMasks = new float[250];
+            m_WorldToDecals = new Matrix4x4[MaxBatchSize];
+            m_NormalToDecals = new Matrix4x4[MaxBatchSize];
+            m_DecalLayerMasks = new float[MaxBatchSize];
 
             m_Sampler = new ProfilingSampler(sampler);
         }

Packages/com.unity.render-pipelines.universal/Runtime/Decal/Entities/DecalEntityManager.cs

@@ -283,9 +283,10 @@ private int CreateChunkIndex(Material material)
             {
                 var propertyBlock = new MaterialPropertyBlock();
 
-                // In order instanced and non instanced rendering to work with _NormalToWorld
-                // We need to make sure array is created with maximum size
-                propertyBlock.SetMatrixArray("_NormalToWorld", new Matrix4x4[250]);
+                // In order instanced and non instanced rendering to work with _NormalToWorld and _DecalLayerMaskFromDecal
+                // We need to make sure the array are created with maximum size
+                propertyBlock.SetMatrixArray("_NormalToWorld", new Matrix4x4[DecalDrawSystem.MaxBatchSize]);
+                propertyBlock.SetFloatArray("_DecalLayerMaskFromDecal", new float[DecalDrawSystem.MaxBatchSize]);
 
                 entityChunks.Add(new DecalEntityChunk() { material = material });
                 cachedChunks.Add(new DecalCachedChunk()