Generate/load pickle key on SSO

[Jujure]

In lifecycle, no pickle key seems to be ever created when logging in through SSO since the pickle key creation is done in setLoggedIn which is not called after attemptDelegatedAuthLogin. Thus when using SSO login, the indexed DB will be stored in plaintext on disk.

This aims to try to generate and load a pickle key in onSuccessfulDelegatedAuthLogin.

Testing strategy:

• On an element-desktop build with keytar
• Sign out/Sign in through SSO
• Check the indexed DB in the dev tools, mx_access_token should be encrypted and not in plaintext

I am still unsure on how to write unit tests about this as the OIDC native flow tests all seems to call setLoggedIn manually but I do not think that this code is actually reachable in the actual app when doing SSO, only doSetLoggedIn is.

I would like to take feedbacks on this before making significant changes to tests I did not write and may not understand completely.

[t3chguy]

Would be good to reuse code rather than duplicate it, especially as the other codepath has helpful logging. Please extract the code from setLoggedIn into a method which both code paths can share.

[Jujure]

Just done that, to avoid different behaviours, setLoggedIn now also tries to load an existing pickle key given the device ID/MXID instead of creating a new one everytime. I don't think this causes any issues but if so, let me know.

[t3chguy]

Looks sane to me other than the prettier fail