Minor Vaultwarden SSO improvements

[0xlua]

This is a followup to #129.

Vaultwarden

While SSO works great so far, I have to frequently re-authenticate in the bitwarden browser extension.
I suspect it is related to the Client Cache

rbw

So far no changes for rbw were needed and it keeps working.
I should still switch to using SSO, details here: doy/rbw#174