Update dependency @types/marked to v6 (#86123)

* Update dependency @types/marked to v6

* remove @types/marked since it's no longer needed

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Ashley Harrison <ashley.harrison@grafana.com>

packages/grafana-data/package.json

@@ -66,7 +66,6 @@
     "@types/dompurify": "^3.0.0",
     "@types/history": "4.7.11",
     "@types/lodash": "4.17.0",
-    "@types/marked": "5.0.2",
     "@types/node": "20.12.7",
     "@types/papaparse": "5.3.14",
     "@types/react": "18.2.78",

packages/grafana-prometheus/package.json

@@ -92,7 +92,6 @@
     "@types/jest": "29.5.12",
     "@types/jquery": "3.5.29",
     "@types/lodash": "4.17.0",
-    "@types/marked": "5.0.2",
     "@types/node": "20.12.7",
     "@types/pluralize": "^0.0.33",
     "@types/prismjs": "1.26.3",