ci: drop npm cache from the docs publish workflow

The publish job has contents: write and triggers a deploy, so restoring an
npm cache that a lower-privileged run could populate is a cache-poisoning
vector. The cache only saved re-downloading the mintlify CLI on a
tag-triggered workflow, so dropping it costs almost nothing.

Author: ericallam

.github/workflows/publish-docs.yml

@@ -22,16 +22,6 @@ jobs:
         with:
           persist-credentials: false
 
-      - name: 📦 Cache npm
-        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
-        with:
-          path: |
-            ~/.npm
-          key: |
-            ${{ runner.os }}-mintlify
-          restore-keys: |
-            ${{ runner.os }}-mintlify
-
       - name: 🔗 Check for broken links
         working-directory: ./docs
         run: npx mintlify@4.0.393 broken-links