Fix the AWS SES migration to sdk v2

[rdimitrov]

Summary

The following PR fixes the migration we did to aws-sdk-go-v2 which caused the email sending service to stop working for minder.

Fixes #4045

Change Type

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• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

Outline how the changes were tested, including steps to reproduce and any relevant configurations.
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Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[stacklok-cloud-staging]

Minder Vulnerability Report ✅

Minder analyzed this PR and found no vulnerable dependencies.

Vulnerability scan of ffde81c6:

• 🐞 vulnerable packages: 0
• 🛠 fixes available for: 0

[coveralls]

coverage: 54.369% (-0.01%) from 54.383%
when pulling fe43dd1 on fix-mail
into 9ef39af on main.