Exchange jwt token with session cookies so that it can work on mobile. Mobile platform is migrating to jwt and for accessing xblocks we need session cookies in exchnage of jwt token. For additional details, see https://github.com/openedx/edx-platform/blob/master/openedx/core/djangoapps/oauth_dispatch/docs/decisions/0013-mobile-migration-to-jwt.rst LEARNER-8518