fix: [ci] Run apt-get update before installing system deps

The shivammathur/setup-php action adds the ondrej/php PPA but the
package index becomes stale, causing 404s when installing PHP packages.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: iglocska

.github/workflows/ci.yml

@@ -134,6 +134,7 @@ jobs:
 
       - name: Install system deps
         run: |
+          sudo apt-get -y update
           sudo apt-get -y install curl python3 python3-pip python3-virtualenv \
             apache2 libapache2-mod-php8.3