chore(create-app): add jest 30 dependencies to template

Add jest and its environment dependencies as devDependencies to the
create-app template, so new Backstage apps are set up with Jest 30
support out of the box.

For Jest 30, apps need @jest/environment-jsdom-abstract and jsdom
instead of jest-environment-jsdom.

Signed-off-by: Johan Persson <johanopersson@gmail.com>

packages/create-app/templates/default-app/package.json.hbs

@@ -32,6 +32,10 @@
     "@backstage/cli": "^{{version '@backstage/cli'}}",
     "@backstage/e2e-test-utils": "^{{version '@backstage/e2e-test-utils'}}",
     "@playwright/test": "^1.32.3",
+    "@jest/environment-jsdom-abstract": "^30.0.0",
+    "@types/jest": "^30.0.0",
+    "jest": "^30.2.0",
+    "jsdom": "^27.1.0",
     "node-gyp": "^10.0.0",
     "prettier": "^2.3.2",
     "typescript": "~5.8.0"