Unset HOME for supervisord.

This matches the way systemd would run supervisord, and avoids
problems with uv finding the cache location.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

entrypoint.sh

@@ -455,6 +455,7 @@ appRun() {
     echo "=== Begin Run Phase ==="
     echo "Starting Zulip using supervisor with \"/etc/supervisor/supervisord.conf\" config ..."
     echo ""
+    unset HOME # avoid propagating HOME=/root to subprocesses not running as root
     exec supervisord -n -c "/etc/supervisor/supervisord.conf"
 }
 appInit() {