Remove Bootstrap logs from IcebergQueryRunner

[ZacBlanco]

Description

Set log level for airlift's Bootstrap log to WARN

Motivation and Context

Should significantly reduce log spam and diagnosing errors easier through the Github Actions UI. ~75% of log messages seem to be from the Bootstrap printing configuration values.

Impact

N/A

Test Plan

N/A

Contributor checklist

• Please make sure your submission complies with our contributing guide, in particular code style and commit standards.
• PR description addresses the issue accurately and concisely. If the change is non-trivial, a GitHub Issue is referenced.
• Documented new properties (with its default value), SQL syntax, functions, or other functionality.
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• Adequate tests were added if applicable.
• CI passed.

Release Notes

== NO RELEASE NOTE ==