Fix failing tests: Update install-wp-tests.sh, Cypress commands, and GitHub Actions workflows

.github/workflows/playground-tests-fix.yml

@@ -19,16 +19,16 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
 
     - name: Setup Node.js
-      uses: actions/setup-node@v4
+      uses: actions/setup-node@60edb5dd545a775178f52524a9de5299b6d2bbed # v4.0.2
       with:
         node-version: '20'
         cache: 'npm'
 
     - name: Install dependencies
-      run: npm ci
+      run: npm ci --legacy-peer-deps
 
     - name: Add WordPress Playground CLI to dependencies
       run: npm install --save-dev @wp-playground/cli