use registerIf to disable metrics in xds cache (#40612)
use registerIf to disable metrics in xds cache (#40612)

* use registerIf to disable metrics in xds cache

Signed-off-by: Rama Chavali <40109507d7c707c570c476fc1522e2d26df7f15e@salesforce.com>

* wrap at creation

Signed-off-by: Rama Chavali <40109507d7c707c570c476fc1522e2d26df7f15e@salesforce.com>

Signed-off-by: Rama Chavali <40109507d7c707c570c476fc1522e2d26df7f15e@salesforce.com>
istio/istio,istio/istio,istio/istio,istio/istio,istio/istio