staging/web: Drop force-ssl-redirect

Otherwise, when hitting this as the reverse proxy backend, we hit a 308 loop (too many
redirects).

Refs. swh/infra/sysadm-environment#5095

swh/values/staging/swh.yaml

@@ -645,7 +645,6 @@ web:
       cert-manager.io/cluster-issuer: letsencrypt-production-gandi
       kubernetes.io/ingress.class: nginx
       kubernetes.io/tls-acme: "true"
-      nginx.ingress.kubernetes.io/force-ssl-redirect: "true"
     tlsEnabled: true
     whitelistSourceRangeRef: stagingNetworkRanges
     endpoints: