Allow scope selector to be hidden by config in tabbed entities search

[MarieVerdonck]

Description

This PR makes the visibility of the search scope selector configurable for related entities searches on simple item pages.

Instructions for Reviewers

The showScopeSelector input is exposed on:

• RelatedEntitiesSearchComponent
• TabbedRelatedEntitiesSearchComponent

and passed through to the underlying ConfigurationSearchPageComponent.

How to test

Set [showScopeSelector]="false" on a tabbed related entities search and verify the scope selector is hidden.
Eg in src/app/entity-groups/research-entities/item-pages/org-unit/org-unit.component.html in ds-tabbed-related-entities-search
=> Verify on OrgUnit simple item page the search doesn't have selector, but on e.g. Person entity simple item page it does

Checklist

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