Add ability to end session for any user profile from the qs user switch widget

[yuriymacdev]

The intent of this feature is to allow the user to quickly end sessions of other profiles in order to save RAM and battery life, if the user doesn't need those users running.

• There is now an online indicator next to the profile, so we can see that the profile is running
• If the user long-clicks on the user icon, he gets a popupmenu with the possibility to end the session for that user.
• I'd prefer to have a green indicator over the classical M3 colors, but in my understanding the M3 standard colors are preferred.
• Now that there is a popup menu action that can end session even for the currently running profile, I suppose it is safe to remove the "End Session" button from the grid (if the button was introduced by GrapheneOS team, not AOSP)
• Any other suggestions or concerns are welcome.

Details:
os-issue-tracker, issue: #2165 (GrapheneOS/os-issue-tracker#2165)

Demo Video:
https://github.com/user-attachments/assets/300fa463-9f40-46c1-9209-3f7b25e96590

screen3.mp4