chore(deps): update dependency @ember/string to v4

Author: renovate[bot]

packages/classic-test-app/package.json

@@ -17,7 +17,7 @@
   "devDependencies": {
     "@ember/legacy-built-in-components": "0.5.0",
     "@ember/optional-features": "2.2.0",
-    "@ember/string": "3.1.1",
+    "@ember/string": "4.0.0",
     "@ember/test-helpers": "3.3.1",
     "@embroider/test-setup": "4.0.0",
     "@glimmer/component": "1.1.2",

packages/test-app/package.json

@@ -22,7 +22,7 @@
     "@babel/plugin-transform-typescript": "7.26.7",
     "@ember/legacy-built-in-components": "0.5.0",
     "@ember/optional-features": "2.2.0",
-    "@ember/string": "3.1.1",
+    "@ember/string": "4.0.0",
     "@ember/test-helpers": "3.3.1",
     "@embroider/test-setup": "4.0.0",
     "@glimmer/component": "1.1.2",

packages/test-esa/package.json

@@ -25,7 +25,7 @@
   "devDependencies": {
     "@ember/legacy-built-in-components": "0.5.0",
     "@ember/optional-features": "2.2.0",
-    "@ember/string": "3.1.1",
+    "@ember/string": "4.0.0",
     "@ember/test-helpers": "3.3.1",
     "@embroider/test-setup": "4.0.0",
     "@glimmer/component": "1.1.2",