chore: pin server to commit before files v4

Signed-off-by: Elizabeth Danzberger <[email protected]>

Author: elzody

.github/workflows/cypress-e2e.yml

@@ -49,7 +49,7 @@ jobs:
         uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
         with:
           repository: nextcloud/server
-          ref: ${{ matrix.server-versions }}
+          ref: $(if [ "${{ matrix.server-versions }}" = "master" ]; then echo -n "d15feb4ba6d003edea664270eb0318faf0de9812"; else echo -n "${{ matrix.server-versions }}"; fi)
 
       - name: Checkout submodules
         shell: bash