Do not log ERROR for watchers in not upgradable scenarios

[michalpristas]

At the moment when we run agent in a container and it's not on usual path but e.g /app/..
we see error saying failed to invoke rollback watcher with a detail explaining executable could not be found.

When running in a container from different path as usual we should

• decrease log level to WARN
• investigate options to skip watcher execution in this scenario

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[jlind23]

@michalpristas as you have self assigned this issue does it mean you are currently working on it?

[jlind23]

@AndersonQ this one could be a pretty good to start ramping up on the agent.

[AndersonQ]

This cannot be reproduced neither on the latest official docker image, docker.elastic.co/beats/elastic-agent:7.16.2, nor on master. Thus I'm closing it

[jlind23]

Thanks @AndersonQ for the work provided.