Feature: Automatically set `istio.values.values.pilot.jwksResolverExtraRootCA` if `sso.certificateAuthority` set

As recently added in Istio 1.17.1-bb.1 (see big-bang/product/packages/istio-controlplane!146 (merged)), we can set istio.values.values.pilot.jwksResolverExtraRootCA to allow the IstioOperator resource (and thereby the istiod deployment) to specify a certificate authority for the JWKS resolver.

This should happen automatically, as this is the intention of the sso.certificateAuthority value.