Add allow/disallow duplicate terraform modules setting to UI

What does this MR do and why?

In Add a setting to allow/disallow duplicate Terra... (!139161 - merged), we added two new settings to the Namespace::PackageSetting model & the corresponding namespace_package_settings database table to allow/disallow publishing duplicate terraform modules:

• terraform_module_duplicates_allowed
• terraform_module_duplicate_exception_regex

Users were able to update those settings only through a GraphQL mutation. In this MR, we are adding the possibility to update the setting through the UI.

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Screenshots or screen recordings

How to set up and validate locally

Navigate to http://gdk.test:3000/groups/<group_full_path>/-/settings/packages_and_registries, you should find the Terraform module duplicate setting under the Duplicate packages section as shown in the screenshot above. You can test toggling it and entering a value in the Exceptions input field.

Related to #368040 (closed)