Integrate @ng-dynamic-forms in code base and upgrade ng-bootstrap version.

[FrancescoMolinaro]

References

Fixes #1272

Description

This PR brings the code from the @ng-dynamic-forms library directly into the DSpace codebase (under src/external-libraries). The upstream library is no longer maintained, and its outdated dependencies were blocking important framework upgrades (e.g., ng-bootstrap).

By decoupling from the external library, we can now upgrade those dependencies and continue improving the components and services originally provided by @ng-dynamic-forms. As part of this migration, the code has already been optimized for newer Angular versions, and all templates have been migrated to use Angular’s control flow syntax.

A notable improvement resulting from the upgrade is the resolution of the accessibility issue related to ngbTypehead. The previously reported aria-multiline violation detected by axe DevTools is no longer present.

Old version:

After upgrade:

The code is under ISC license so all the files will contain a copy of the license text specified in the repo: https://github.com/udos86/ng-dynamic-forms?tab=ISC-1-ov-file

Instructions for Reviewers

This PR does not introduce new features. All library components should behave and appear the same as before. The focus is strictly on migrating and updating the code.

List of changes in this PR:

Integrated the relevant portions of @ng-dynamic-forms (core and ui-ng-bootstrap) into the repository under src/external-libraries/ng-dynamic-forms/.

Updated tsconfig paths and imports across the application:

"@ng-dynamic-forms/core/": ["src/external-libraries/ng-dynamic-forms/core/"]
"@ng-dynamic-forms/ui-ng-bootstrap/": ["src/external-libraries/ng-dynamic-forms/ui-ng-bootstrap/"]

Upgraded ng-bootstrap to v15.1.2 and updated imports where needed (module → standalone).

Migrated all library templates to Angular's control flow syntax.

Applied ESLint fixes where possible within the migrated library code.

Test:

To verify the fix for the aria-multiline accessibility issue:

1. Use axe DevTools on any form containing:
   a dynamic-onebox component, or
   any component using the ngbTypehead directive.

2. In the current main branch, axe should report the aria-multiline violation.

3. When testing the same form with this PR, the violation should no longer appear.

Checklist

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However, reviewers may request that you complete any actions in this list if you have not done so. If you are unsure about an item in the checklist, don't hesitate to ask. We're here to help!

• My PR is created against the main branch of code (unless it is a backport or is fixing an issue specific to an older branch).
• My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• My PR passes ESLint validation using npm run lint
• My PR doesn't introduce circular dependencies (verified via npm run check-circ-deps)
• My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• My PR aligns with Accessibility guidelines if it makes changes to the user interface.
• My PR uses i18n (internationalization) keys instead of hardcoded English text, to allow for translations.
• My PR includes details on how to test it. I've provided clear instructions to reviewers on how to successfully test this fix or feature.
• If my PR includes new libraries/dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.
• If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• If my PR fixes an issue ticket, I've linked them together.