VxSuite: Remove power down buttons from all machines that have physical power buttons AND remove restart buttons from "Something went wrong" screens

[arsalansufi]

Let's remove the UI power down buttons from all machines that have physical power buttons. This means that only VxScan needs such a power down button.

We should also remove the restart buttons from "Something went wrong" screens as those buttons require the backend to be running and the backend may have (in fact likely) crashed. So in most cases, those buttons won't do anything.

Relevant Slack threads:

• https://votingworks.slack.com/archives/CJU9MSC6S/p1722453881850639?thread_ts=1722453881.850639&cid=CJU9MSC6S
• https://votingworks.slack.com/archives/CJU9MSC6S/p1722975786885349