Create notificationAccount, get identity_keys(), and dispatch setNotificationIdentityKeys action to store in Redux cryptoStore.
Note that all the logic on whether to eg enable login button, etc is still only dependent on identityED25519... this will be addressed in subsequent diffs.
Depends on D6877
Can we extract this to its own line? Similar to how we want await to be visible, I think it's good for hooks to be as well