Fixed ColorParameter showEyeDropper not being properly set

ScriptableRenderPipeline/Core/Volume/VolumeParameter.cs

         {
             this.hdr = hdr;
             this.showAlpha = showAlpha;
+            this.showEyeDropper = showEyeDropper;
             this.overrideState = overrideState;
         }
 
         {
             this.hdr = hdr;
             this.showAlpha = showAlpha;
+            this.showEyeDropper = showEyeDropper;
             this.overrideState = overrideState;
         }
     }