Breadcrumbs disappear on issue overview when no results are found

Problem/Motivation

When the issue queue returns no results (e.g. because the query is too specific or there are no open issues) then the breadcrumbs disappear which makes it difficult for the user to go back to the project's page.

Steps to reproduce

Search a project's issue queue in a way that yields no results

Proposed resolution

Ensure the breadcrumbs are also displayed when there are no results in the view.

Remaining tasks

User interface changes

API changes

Data model changes