Enable Lightbox compatibility with Lazy Loading

[AnthonyLedesma]

Description

Fixes #2582

Enhance the Lightbox script logic to allow for Lightbox with A3 Lazy Load plugin. Source the image from data-src attribute if the src contains 'lazy-load'.

Screenshots

Types of changes

Lightbox JavaScript changes.

How has this been tested?

Tested manually.

Acceptance criteria

Should allow Lightbox to function when A3 Lazy Load is enabled.

Checklist:

• [x] My code is tested
• [x] My code follows accessibility standards
• [x] My code has proper inline documentation
• [x] I've included any necessary tests
• [x] I've included developer documentation
• [x] I've added proper labels to this pull request