Add validation test to webgpu

tests/validation/webgpu.json

@@ -119,6 +119,11 @@
             "title": "depth renderer",
             "renderCount": 5,
             "playgroundId": "#1PHYB0#86"
+        },
+        {
+            "title": "particle system with custom nme shader",
+            "renderCount": 5,
+            "playgroundId": "#DMLLV2"
         }
     ]
 }