Fix: make alert for new sections fully translatable (#4740)

[guillermo-escire]

References

• Fixes Alert for new sections not fully translatable #4740

Description

This PR improves internationalization support for submission alerts when new sections are dynamically added.
Instead of using a partially translatable message, the alert now supports fully translatable i18n keys per section, with a fallback to the generic message when a specific translation is not available.

Summary of changes

• Updated submission.service.ts to generate section-specific i18n keys for the “new section added” alert.
• Allows translations to be defined per section (e.g. duplicates) while maintaining backward compatibility via a fallback key.

Instructions for Reviewers

1. Start the Angular UI and create a new submission.
2. Add metadata that triggers a new section to appear (for example, trigger the duplicates section by submitting metadata that already exists in the database).
3. Observe the notification alert shown in the upper-right corner.
4. Verify that:
   • The alert message is fully translatable.
   • A section-specific i18n key is used when available.
   • The generic fallback message is used if no section-specific translation exists.

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[tdonohue]

@guillermo-escire : Please add a description to this PR including how to test it. All PRs must provide basic instructions for how reviewers are to test them. I've already added the link back to the issue you are fixing (which is also required), but I'll leave the rest of the description for you to fill out.