Re-enable Ceph dashboard SSL to fix SAML http/https URL mismatch

X-Forwarded-Proto approach didn't work - Ceph dashboard SAML doesn't
read it. Re-enabling native SSL so the dashboard sees https:// URLs
directly. Updated both Istio and Envoy Gateway backends for TLS with
insecureSkipVerify for the self-signed cert.

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

infrastructure/rook-ceph/manifests/envoy-route.yaml

@@ -17,12 +17,6 @@ spec:
         - path:
             type: PathPrefix
             value: /
-      filters:
-        - type: RequestHeaderModifier
-          requestHeaderModifier:
-            set:
-              - name: X-Forwarded-Proto
-                value: https
       backendRefs:
         - group: gateway.envoyproxy.io
           kind: Backend