oxlog does not find archived live log files

[davepacheco]

#9226 added archival of live log files from zones when they shut down and when the sled reboots. But they get named slightly differently and oxlog doesn't find them. After a recent dogfood update:

BRM27230045 # ls -1 /pool/ext/*/crypt/debug/*nexus_dcb*/*nexus* > all_logs.txt

BRM27230045 # /opt/oxide/oxlog/oxlog logs oxz_nexus_dcb27edf-5a97-459a-92c0-63d795744055 nexus --archived > oxlog_logs.txt

BRM27230045 # diff oxlog_logs.txt all_logs.txt 
137a138,139
> /pool/ext/8a0016f3-3cdc-4b4c-b1d3-5334dd365465/crypt/debug/oxz_nexus_dcb27edf-5a97-459a-92c0-63d795744055/oxide-nexus:default.1761086667
> /pool/ext/8a0016f3-3cdc-4b4c-b1d3-5334dd365465/crypt/debug/oxz_nexus_dcb27edf-5a97-459a-92c0-63d795744055/oxide-nexus:default.1761098396

There are two choices here:

• teach oxlog about these paths. (pro: will cover files already archived with this problem. risk: is there some other file in these datasets that it will mistakenly pick up?)
• change sled agent to preserve the .log in this case. This seems better, but would require more testing (this code is not factored in a way that makes it testable without fully running it all, including archiving on a deployed system) and oxlog would never pick up log files that had been archived without this fix.