Update config.json (#4115)

Test to see if removing `square-root` affects the availability of `triangle`.

Author: BethanyG

config.json

@@ -594,7 +594,7 @@
         "slug": "square-root",
         "name": "Square Root",
         "uuid": "c32f994a-1080-4f05-bf88-051975a75d64",
-        "practices": ["numbers"],
+        "practices": [],
         "prerequisites": ["basics", "numbers", "conditionals", "loops"],
         "difficulty": 2
       },