Update dependency ember-cli to ~6.9.1 (#1685)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

playground/ember/package.json

@@ -56,7 +56,7 @@
     "concurrently": "^9.2.1",
     "decorator-transforms": "^2.3.0",
     "ember-auto-import": "^2.12.0",
-    "ember-cli": "~6.8.1",
+    "ember-cli": "~6.9.1",
     "ember-cli-babel": "^8.2.0",
     "ember-cli-htmlbars": "^6.3.0",
     "ember-load-initializers": "^3.0.1",