Update dependency @ember/string to v4

Author: renovate[bot]

package.json

@@ -40,7 +40,7 @@
     "@babel/eslint-parser": "7.28.4",
     "@babel/plugin-proposal-decorators": "7.28.0",
     "@ember/optional-features": "2.2.0",
-    "@ember/string": "3.1.1",
+    "@ember/string": "4.0.1",
     "@ember/test-helpers": "2.9.6",
     "@embroider/test-setup": "1.8.3",
     "@glimmer/component": "1.1.2",