AWSX-1182 Override DD_LOG_LEVEL env var to WARN in the forwarder template

[ge0Aja]

What does this PR do?

Overrides the log level to WARN to avoid having the forwarder info logs by default.

Motivation

Testing Guidelines

Additional Notes

Types of changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

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