chore(fast-html): use @microsoft/fast-build to build lifecycle-callbacks fixture

[janechu]

Pull Request

📖 Description

Adds the lifecycle-callbacks test fixture to @microsoft/fast-html and generates its index.html using @microsoft/fast-build, consistent with the other fixtures (attribute, binding, event, ref, slotted, when, repeat, repeat-event, children).

The lifecycle-callbacks fixture covers FAST element lifecycle callbacks (connectedCallback, disconnectedCallback, attributeChangedCallback) and deferred hydration via the needs-hydration and defer-hydration attributes. It verifies that SSR correctly renders initial state for elements using these lifecycle patterns, and that FAST properly hydrates and activates bindings after connection.

🎫 Issues

No open issues directly addressed.

📑 Test Plan

• npm run build:fixtures in packages/fast-html runs cleanly and regenerates lifecycle-callbacks/index.html with correct shadow DOM content rendered from root state.
• All other fixture outputs are unchanged.

✅ Checklist

General

• I have included a change request file using $ npm run change
• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.