login: the azure cli task in azure devops takes >1 minute to even start

Ok, basically no matter how you try to use az cli in azure devops on a microsoft-hosted build agent, the first command (usually az login) will take over a minute to complete. This is a very long time when you're waiting for a build to complete that otherwise takes less than 10 seconds.

I don't know exactly what az cli is doing, but whatever it is, there must be less of it.

## steps to reproduce

Have a build in azure devops, set to run on a microsoft hosted vs2017 build agent.
Add a azure cli build step, connect it to any valid service principal, set the inline script to echo "".
Run the build.
Watch the azure cli build step take 75 seconds to complete.

I figure acceptable numbers here are something like 5 seconds.