Automatically select authenticator stage text box when logging in

**Is your feature request related to a problem? Please describe.**
After a user inputs their username and password, and the next stage is the 2fa authenticator code stage, the box to enter the 2fa code isn't automatically selected to allow for immediate input of the code, the box needs to be selected first.

**Describe the solution you'd like**
For the authenticator text box to be automatically selected when going to the authenticator stage.

**Describe alternatives you've considered**
N/A

**Additional context**
N/A

The issue names no files, tests, or entry points. Start by locating the authenticator stage's text-box component and the transition into that stage, then verify the box receives focus when the stage appears and that the existing login flow still works.

Written by the indexing model from the issue text.