fix: resolve file:data:: references on deployment attachment_urls

[sovadim]

Applicable issues

• fixes attachment_urls on dial_deployment tools fail on file:data:: references #518

Description of changes

Fixes the insertion of attached file content into a message.

Checklist

• Title of the pull request follows Conventional Commits specification
• Design documented is updated/created and approved by the team (if applicable)
• Documentation is updated/created (if applicable)
• Changes are tested on review environment
• App schema changes are backward compatible, or breaking changes are documented with a migration guide
• Integration tests pass

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.