Remove deprecated lines in Husky pre-commit script (#13396)

* Remove deprecated lines in pre-commit script. Test commit

* Remove deprecated lines in pre-commit script

* Test commit

* Revert test changes

* Revert test changes

* Remove install keyword from setup script in package.json

---------

Co-authored-by: Jonas Dyrlie <jonas.dyrlie@gmail.com>

.husky/pre-commit

@@ -1,4 +1 @@
-#!/usr/bin/env sh
-. "$(dirname -- "$0")/_/husky.sh"
-
 yarn lint-staged

package.json

@@ -83,7 +83,7 @@
     "lint:fix": "yarn run lint --fix",
     "codestyle:check": "prettier frontend --check",
     "codestyle:fix": "prettier frontend --write",
-    "setup": "husky install && node development/setup.js && yarn run git:ignore-revs",
+    "setup": "husky && node development/setup.js && yarn run git:ignore-revs",
     "sort-texts": "yarn workspace @altinn-studio/language run sort",
     "start-app-development": "yarn workspace app-development start",
     "start-app-preview": "yarn workspace app-preview start",