Update UI base images for AudioQnA and ChatQnA

[ZePan110]

Description

The summary of the proposed changes as long as the relevant motivation and context.

Issues

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Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds new functionality)
• Breaking change (fix or feature that would break existing design and interface)
• Others (enhancement, documentation, validation, etc.)

Dependencies

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Tests

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[github-actions]

⚠️ WARNING
File AudioQnA/ui/docker/Dockerfile resulted in a change in the image size from 1471 -> 1644 MB (diff: 173 MB)

[Copilot]

Pull request overview

This PR updates the base Docker image for the AudioQnA UI component from a specific Node.js version to an Alpine-based variant for improved efficiency and smaller image size.

Changes:

• Updated Node.js base image from version-pinned to Alpine variant

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[github-actions]

⚠️ WARNING
File AudioQnA/ui/docker/Dockerfile resulted in a change in the image size from 1471 -> 1644 MB (diff: 173 MB)

[github-actions]

⚠️ WARNING
File AudioQnA/ui/docker/Dockerfile resulted in a change in the image size from 1471 -> 1644 MB (diff: 173 MB)
⚠️ WARNING
File ChatQnA/ui/docker/Dockerfile resulted in a change in the image size from 1419 -> 1599 MB (diff: 180 MB)