For top-level sites the partitionKey in use differs depending on the component: * network cache always uses the partitionedPrincipal having a non-empty partitionKey even on top-level loads * cookies and other components use the empty partitionKey for top-level-loads. With this patch each component is cleaned with the correct partitionKey for the component. Differential Revision: https://phabricator.services.mozilla.com/D239760