Add S3 upload step to base installer workflow for automatic updates

[Copilot]

This PR adds S3 upload functionality to the base installer continuous deployment workflow to support automatic updates in FieldWorks.

Problem

The base installer workflow (base-installer-cd.yml) was missing the S3 upload step needed to make base installers available for automatic updates. The patch installer workflow already had this functionality, but base installers were not being uploaded to the expected S3 location that the automatic update system looks for.

Solution

Added two new steps to the base installer workflow following the same pattern as the patch installer workflow:

1. Configure AWS credentials - Sets up AWS authentication using the same secrets and configuration
2. Upload Installers to S3 - Uploads both online and offline installers to the correct S3 path

Technical Details

• S3 Location: s3://flex-updates/jobs/FieldWorks-Win-all-Release-Base/${RELEASE_BASE_BUILD_NUMBER}/
• Files Uploaded: Both FieldWorks_*_Online_x64.exe and FieldWorks_*_Offline_x64.exe
• Condition: Only uploads when make_release == 'true' (matching existing release logic)
• Integration: Uses existing installer file paths from the stage_installers step

The S3 path structure matches exactly what the automatic update system expects based on the patterns defined in Src/Common/FwUtils/FwUtilsTests/FwUpdaterTests.cs:

private static string BaseKey(string version, int baseBuild, int arch, bool isOnline)
{
    return $"jobs/FieldWorks-Win-all-Release-Base/{baseBuild}/{BaseFileName(version, arch, isOnline)}";
}

Validation

• ✅ YAML syntax validated
• ✅ S3 path matches expected pattern from test files
• ✅ Follows same AWS configuration as patch installer workflow
• ✅ Proper error handling and logging included
• ✅ Only runs when releasing (not on test builds)

This change enables the automatic update system to find and download base installers, completing the S3 upload coverage for both patch and base installers.

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This change is 

[jasonleenaylor]

@jasonleenaylor reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @copilot)

[jasonleenaylor]

Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @copilot)