feat: add fields located outside the Properties block in the shader as Animatable Properties

close #399

Samples~/Demo/Animations/ColorArrayInjection.cs

@@ -0,0 +1,32 @@
+using System.Linq;
+using UnityEngine;
+
+[RequireComponent(typeof(ParticleSystemRenderer))]
+public class ColorArrayInjection : MonoBehaviour
+{
+    [SerializeField] private string m_PropertyName = "_Color2";
+
+    [SerializeField] private Color[] m_Colors = new Color[4]
+    {
+        Color.red,
+        Color.green,
+        Color.blue,
+        Color.yellow
+    };
+
+    private void OnEnable()
+    {
+        if (TryGetComponent<ParticleSystemRenderer>(out var psr))
+        {
+            var mpb = new MaterialPropertyBlock();
+            psr.GetPropertyBlock(mpb);
+            mpb.SetVectorArray(m_PropertyName, m_Colors.Select(x => new Vector4(x.r, x.g, x.b, 1.0f)).ToArray());
+            psr.SetPropertyBlock(mpb);
+        }
+    }
+
+    private void OnValidate()
+    {
+        OnEnable();
+    }
+}

Samples~/Demo/Animations/ColorArrayInjection.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: da4c2e90ecd3d4dd4a520099c08cf493
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: