Disable 2fa in rocketchat for proper CI testing

When using SSO in CI with taiko (!413 (merged)), rocketchat requires 2fa login which is not possible in CI. We also want to integrate 2fa centrally in our SSO system so apps should not use it by themselves.

Disabling 2fa was added in this MR, however I'm not sure how to configure it with the rocketchat helm chart.