Query Mist without mdmclient validation

[jtwillbanks]

Testing a solution to allow Super to query Mist for minor or major version targets even if mdmclient does not return the full macOS installer items.

Updates mist CSV parsing to skip only the CSV header row with "awk" instead of the previous sed range expression. In testing the old method could produce an empty list for _macos_installers_list_ when it began with an identifier header.

Previously, get_macos_installers_list() was only called if mdmclient_macos_installer_array was non-empty. In some cases, mdmclient only reports the latest OTA/MSU macOS update. This would prevente InstallMacOSMinorVersionTarget from targeting an available full installer when the requested version was not exposed by mdmclient.

Also the retry error handling for installer list now also checks get_macos_installers_list_error and get_macos_installers_list_timeout instead of the mdmclient error variables

Test Expression Used
sudo super --reset-super --install-macos-minor-version-target=26.4.1 --verbose-mode --workflow-only-download

[Macjutsu]

Thanks for taking time to develop this alternate method...

However, I'm unlikely to implement this in the current build of super because I plan to fully remove mdmclient in a future (soon-ish) version of super. I'll leave this open for inspiration.