Rename Collect Agent Host Debug Logs action to Export, download remote agenthost.log (#314884)

* Rename Collect Agent Host Debug Logs to Export, download remote agenthost.log

- Rename action 'Collect Agent Host Debug Logs' to 'Export Agent Host Debug Logs...'
- Rename command id agentHost.collectDebugLogs -> agentHost.exportDebugLogs
- For remote agent host sessions, also download the remote agenthost.log
  from the server's logs directory ($HOME/<serverDataFolderName>/data/logs/<latest>/agenthost.log)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Broaden remote agenthost.log folder candidates

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Use joinPath for URI path manipulation

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Pick globally newest agenthost.log across all candidate folders

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>