Remove json_validate function and its corresponding unit tests as they are no longer required.

Author: jturbide

composer.json

@@ -143,8 +143,7 @@
     "files": [
       "src/Functions/Dump.php",
       "src/Functions/Array.php",
-      "src/Functions/Sprintf.php",
-      "src/Functions/Json.php"
+      "src/Functions/Sprintf.php"
     ]
   },
   "autoload-dev": {