Add user helmet safety icon to Nimble and Spright

[vivinkrishna-ni]

Pull Request

🤨 Rationale

Part of #2868

Add a work item Job icon for one of the workflows in SLE.

👩‍💻 Implementation

1. Added the "User Helmet Safety" icon to Nimble, following the standard icon‑addition pattern. For the workflow, it will be used for a Job-type work item; however, the icon is generic, so we followed the same name from the Font Awesome Icons.
2. Added the same User Helmet Safety icon to the Spright icon set, as a colored variant is required.
3. Introduced the necessary Spright Angular directive to support the new icon.

🧪 Testing

Test the build from the storybook publish.

✅ Checklist

• I have updated the project documentation to reflect my changes or determined no changes are needed.

[jattasNI]

@rajsite I verified the naming matches font-awesome and other patterns match existing icons, so gonna bypass you on this.