Add a check for the number 0 (which is for checking score set to 0) (#…

…10004)

This adds a validator plan to check for the number 0 block, which is useful if we want to ensure 0 was passed in as a parameter (used by microsoft/pxt-microbit#5644 to check for setting lives to 0 specifically, which produces output when non-zero values do not)

common-docs/teachertool/validator-plans-shared.json

@@ -281,6 +281,19 @@
                     "name": ""
                 }
             ]
+        },
+        {
+            ".desc": "The zero number block is present.",
+            "name": "number_zero",
+            "threshold": 1,
+            "checks": [
+                {
+                    "validator": "blockFieldValueExists",
+                    "fieldType": "NUM",
+                    "fieldValue": 0,
+                    "blockType": "math_number"
+                }
+            ]
         }
     ]
 }