Avoid using default provider chain in tests (#4229)

## Motivation and Context
The previous tests mistakenly used the default credentials provider
chain, which led to test failures during a release. This occurred
because the chain hit a credentials provider that made a remote call
(e.g., IMDS), causing the captured request to be exhausted, leading to a
panic. To address this issue, the PR avoids using the default
credentials provider chain.

## Testing
~Currently verifying in the release pipeline~ Verified 

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