Allow SpeculationRules prefetch for ServiceWorker-controlled URLs

Controls whether SpeculationRules prefetch requests are allowed for ServiceWorker-controlled URLs. With Microsoft Edge version 138, prefetch requests to ServiceWorker-controlled URLs are allowed by default when the PrefetchServiceWorker feature is enabled. If this policy is enabled or not configured, that default behavior is used. To restore the legacy behavior from versions before 138, where prefetch requests to ServiceWorker-controlled URLs were blocked, set this policy to disabled. This policy is intended to be temporary and will be removed in the future.