update priority screenshots for Qubes 4.1

[cfm]

Towards #105, updates priority screenshots—i.e., those that will be helpful for upcoming guided installations with pilot participants—for Qubes 4.1, per #105 (comment).

Checklist

• In GitHub's visual diff, screenshots are correct and identical except for the intended differences between Qubes 4.0 and 4.1.

[eloquence]

Looks good! Merging without forwarding stable tag until the main 4.1 docs PR lands.

A minor thing we may want to standardize going forward is the username used in screenshots. I used nbly as a fake journalist name, but we should probably just standardize on user since that's what we recommend using in the install docs.

[cfm]

Fair, but tricky when the screenshot machine is also a developer's primary workstation. (Which this machine isn't yet, but it will be soon!) I would consider redaction to be adequate to avoid confusion (not really to provide any privacy); would you, @eloquence?