fix: remove unnecessary dependencies install step from spell check

The spell check uses npx cspell which doesn't require project
dependencies to be installed. The jlpm install step was causing
authentication failures when trying to fetch @deepnote/blocks.

Author: devin-ai-integration[bot]

.github/workflows/ci.yaml

@@ -27,10 +27,5 @@ jobs:
       - name: Install JupyterLab
         run: python -m pip install -U "jupyterlab>=4.0.0,<5"
 
-      - name: Install dependencies
-        run: jlpm install --frozen-lockfile
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
       - name: Run spell check
         run: npx [email protected] "**/*.{md,txt,json,js,ts,tsx,jsx,yml,yaml}"