perf: remove validation-context cache from stage-and-check

Agent-Logs-Url: https://github.com/nextcloud/documentation/sessions/a5960894-fe91-499f-9354-43d805393a25

Co-authored-by: skjnldsv <14975046+skjnldsv@users.noreply.github.com>

Author: Copilot

.github/workflows/sphinxbuild.yml

@@ -244,20 +244,6 @@ jobs:
       # 2. Merge in the new artifacts (what we're about to deploy)
       # 3. Run link checks only on the NEW content, but with full context
       # ========================================================================
-      # ========================================================================
-      # FETCH GH-PAGES FOR LINK VALIDATION CONTEXT
-      # ========================================================================
-      # We cache the gh-pages checkout between runs so that repeated workflow
-      # runs (e.g. on pull requests) don't have to re-fetch the full gh-pages
-      # branch every time.
-      # ========================================================================
-      - name: Cache gh-pages content for validation context
-        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
-        with:
-          path: validation-context/
-          key: gh-pages-content-${{ github.run_id }}
-          restore-keys: gh-pages-content-
-
       - name: Checkout gh-pages branch for validation context
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with: