fix: Session cookie passing after successful resource finder

When user init the login flow, first app tries to retrieve the DAV
providers info by making DAV request via DavResourceFinder. In this
stage, no account is created, so inMemoryCookieStore is used. After
successful resource info retrieval then account is created & then
refreshed the collection via RefreshCollectionWorker. As previously only
inMemory cookieJar is used, the refreshCollection makes it's first
request without any cookie, which causes extra server headace.

To mitigate this, we need to persist the last inMemory cookies after
successful resource retrieval.