Adjust how Dashboard link is removed from the Administration menu for the Navigation bar

Problem/Motivation

We are adding a block for showing our link in the navigation, so we remove it from the menu itself.
This means that the Administration menu is altered everywhere the Administration menu is used instead of just the place we need it altered within the Navigation bar. For instance, when you go into the Admin UI for the Adminstration menu (/admin/structure/menu/manage/admin), those Help and Content links are gone. This could be very unexpected for other modules using the Administration menu.

See 📌 Adjust how Help link and Content links are removed from the Administration menu for the Navigation bar RTBC

Steps to reproduce

Proposed resolution

Postponed on 📌 Adjust how Help link and Content links are removed from the Administration menu for the Navigation bar RTBC

Remaining tasks

User interface changes

API changes

Data model changes