merge multiplier field in HDProbe

com.unity.render-pipelines.high-definition/HDRP/Lighting/Reflection/HDAdditionalReflectionData.cs

         int m_Version;
 
         public ShapeType influenceShape;
-        [FormerlySerializedAsAttribute("dimmer")]
-        public float multiplier = 1.0f;
         [Range(0.0f, 1.0f)]
         public float weight = 1.0f;
         public float influenceSphereRadius = 3.0f;

com.unity.render-pipelines.high-definition/HDRP/Lighting/Reflection/HDProbe.cs

         [SerializeField, FormerlySerializedAs("proxyVolumeComponent"), FormerlySerializedAs("m_ProxyVolumeReference")]
         ReflectionProxyVolumeComponent m_ProxyVolume = null;
 
+        [SerializeField, FormerlySerializedAsAttribute("dimmer"), FormerlySerializedAsAttribute("m_Dimmer"), FormerlySerializedAsAttribute("multiplier")]
+        float m_Multiplier = 1.0f;
+
+        public float multiplier { get { return m_Multiplier; } }
     }
 }

com.unity.render-pipelines.high-definition/HDRP/Lighting/Reflection/PlanarReflectionProbe.cs

         [SerializeField]
         Vector3 m_CaptureLocalPosition;
         [SerializeField]
-        [FormerlySerializedAsAttribute("m_Dimmer")]
-        float m_Multiplier = 1.0f;
-        [SerializeField]
         [Range(0.0f, 1.0f)]
         float m_Weight = 1.0f;
         [SerializeField]
         public Bounds bounds { get { return m_InfluenceVolume.GetBoundsAt(transform); } }
         public Vector3 captureLocalPosition { get { return m_CaptureLocalPosition; } set { m_CaptureLocalPosition = value; } }
         public float weight { get { return m_Weight; } }
-        public float multiplier { get { return m_Multiplier; } }
         public ReflectionProbeMode mode { get { return m_Mode; } }
         public Matrix4x4 influenceToWorld
         {