[ENHC0010017] Change download paths to use rails_blob_path

[ChrisHuynh333]

What does this PR do and why?

This PR changes from using the download endpoints for sample attachments and data exports to utilizing the Rails helper rails_blob_path to download the files.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other pull requests.

How to set up and validate locally

1. Ensure you are able to create and download both sample and workflow execution exports
2. Ensure you can download both single and paired-end sample files.

PR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• [x] I have evaluated the PR acceptance checklist for this PR.

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Simplecov Report

Covered	Threshold
92.21%	90%