HDRenderPipeline: Move remove tessellation option to a debug submenu

to avoid artist mistake

Assets/ScriptableRenderPipeline/HDRenderPipeline/Editor/HDRenderPipelineMenuItems.cs

             }
         }
 
-        [MenuItem("HDRenderPipeline/Remove tessellation materials (not reversible)")]
+        [MenuItem("HDRenderPipeline/Debug/Remove tessellation materials (not reversible)")]
         static void RemoveTessellationMaterials()
         {
             Object[] materials = Resources.FindObjectsOfTypeAll<Material>();