credentials precedence in release >= 3.2.1297.0

Hi,

I suspect that release **3.2.1297.0** introduced a, perhaps involuntary, change in the credentials precedence logic. What we are experiencing in all our EC2 managed instances is that the agent (for instance when running AWS-RunPatchBaseline) is using the default profile credentials from `/root/.aws/credentials` instead of the EC2 instance profile role. Versions before 3.2.1297.0 were using the instance profile role although there was a `/root/.aws/credentials` present.

To make things more confusing, the [documentation](https://docs.aws.amazon.com/systems-manager/latest/userguide/ssm-agent-technical-details.html) states that the precedence should indeed be `/root/.aws/credentials` first and EC2 instance profile role last but only for _"SSM Agent version 3.1.1927.0 or earlier, and for Amazon ECS container instances"_. In our case none of the instances is an ECS container instance and all of them are running amazon-ssm-agent version 3.2.1297.0.

Furthermore, in the same documentation page it is clearly stated that (highlighting is mine)

> **Starting with version 3.2.183.0** of SSM Agent, the agent stores a set of temporary credentials at /var/lib/amazon/ssm/credentials (for Linux and macOS) or %PROGRAMFILES%\Amazon\SSM\credentials (for Windows Server). The temporary credentials have the permissions you specify for the IAM role you chose for Default Host Management Configuration, **or the instance profile attached to your managed node.**

This part of the documentation is not mentioning `/root/.aws/credentials` at all, so I guess starting with version 3.2.183.0 the Default Host Management Configuration or the instance profile role is used.

I understand that the documentation might be out of sync. Nevertheless, releases before **3.2.1297.0** were not using (or not giving higher precedence)`/root/.aws/credentials` but release **3.2.1297.0** does. So my question is first what is the expected behaviour of release **3.2.1297.0** regarding the credentials precedence and second do you believe that the documentation is reflecting this precedence?

Reproduce the credential selection on amazon-ssm-agent 3.2.1297.0 with both /root/.aws/credentials and an EC2 instance profile, then compare it with an earlier version. Trace the credential resolution entry point and review the linked AWS documentation; done means the expected precedence is established and the agent behavior and documentation agree.

Written by the indexing model from the issue text.