consider removing prompt when installing plugin

krew, kubectls plugin manager displays the following message instead of prompting to confirm installation of the plugin:

WARNING: You installed plugin "reverse-proxy" from the krew-index plugin repository.
   These plugins are not audited for security by the Krew maintainers.
   Run them at your own risk.

It would be nice to let people know they installed something we have not audited and skip the prompt step. I don't there is ever going to be a time when I say no and I always forget to use the --yes flag.

I'd love to see either of the following:

• Map environment variable to value of the --yes flag so that you could set false if you are more cautious and want to be prompted.
• Make default behavior more like krew's warning rather than prompting to confirm installation

Start by locating the Spin CLI code that handles plugin installation and the existing --yes confirmation path. Compare the requested environment-variable behavior with changing the default to a warning, then verify that installation proceeds without an unwanted prompt while cautious users can still require confirmation.