🔥(frontend) remove grapesjs dependencies

Some grapesjs dependencies were still present.
We don't use these anymore, so we can remove them.

src/frontend/apps/impress/package.json

@@ -21,7 +21,6 @@
     "@gouvfr-lasuite/integration": "1.0.1",
     "@openfun/cunningham-react": "2.9.3",
     "@tanstack/react-query": "5.48.0",
-    "grapesjs-blocks-basic": "1.0.2",
     "cross-env": "*",
     "i18next": "23.11.5",
     "lodash": "4.17.21",
@@ -53,7 +52,6 @@
     "dotenv": "16.4.5",
     "eslint-config-impress": "*",
     "fetch-mock": "9.11.0",
-    "grapesjs": "0.21.11",
     "jest": "29.7.0",
     "jest-environment-jsdom": "29.7.0",
     "node-fetch": "2.7.0",