remove obsolete 'core-js' package

In the past we used core-js to support features that the browsers didn't support
back then, it is safe to remove now

package.json

@@ -117,7 +117,6 @@
     "@testing-library/react": "12",
     "@testing-library/user-event": "^14.4.3",
     "babel-jest": "^24.9.0",
-    "core-js": "^2.6.3",
     "coveralls": "^3.0.9",
     "cypress": "^10.1.0",
     "enzyme": "^3.11.0",

yarn.lock

@@ -3586,7 +3586,7 @@ core-js-pure@^3.20.2:
   resolved "https://registry.yarnpkg.com/core-js-pure/-/core-js-pure-3.23.2.tgz#efe5e486469c5ed2d088d76e973eb12e74a930e7"
   integrity sha512-t6u7H4Ff/yZNk+zqTr74UjCcZ3k8ApBryeLLV4rYQd9aF3gqmjjGjjR44ENfeBMH8VVvSynIjAJ0mUuFhzQtrA==
 
-core-js@^2.4.0, core-js@^2.6.12, core-js@^2.6.3, core-js@^2.6.5:
+core-js@^2.4.0, core-js@^2.6.12, core-js@^2.6.5:
   version "2.6.12"
   resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.6.12.tgz#d9333dfa7b065e347cc5682219d6f690859cc2ec"
   integrity sha512-Kb2wC0fvsWfQrgk8HU5lW6U/Lcs8+9aaYcy4ZFc6DDlo4nZ7n70dEgE5rtR0oG6ufKDUnrwfWL1mXR5ljDatrQ==