Fix uncaught ClassCastException from invalid recipe file (#4043)

A JsonSyntaxException will now be thrown, caught and logged when the conditions property of a recipe isn't an array

src/main/java/net/minecraftforge/common/crafting/CraftingHelper.java

@@ -735,7 +735,7 @@ public class CraftingHelper {
                 {
                     reader = Files.newBufferedReader(f);
                     JsonObject json = JsonUtils.fromJson(GSON, reader, JsonObject.class);
-                    if (json.has("conditions") && !CraftingHelper.processConditions(json.getAsJsonArray("conditions"), ctx))
+                    if (json.has("conditions") && !CraftingHelper.processConditions(JsonUtils.getJsonArray(json, "conditions"), ctx))
                         continue;
                     IRecipe recipe = CraftingHelper.getRecipe(json, ctx);
                     ForgeRegistries.RECIPES.register(recipe.setRegistryName(key));

src/test/resources/assets/crafting_system_test/recipes/conditions_property_not_array.json

@@ -0,0 +1,21 @@
+{
+  "conditions": {
+    "not an array": "conditions property must be an array"
+  },
+  "type": "crafting_shaped",
+  "group": "planks",
+  "pattern": [
+    "#"
+  ],
+  "key": {
+    "#": {
+      "item": "minecraft:log2",
+      "data": 0
+    }
+  },
+  "result": {
+    "item": "minecraft:planks",
+    "data": 4,
+    "count": 4
+  }
+}