Slash is not required in app urls

### Description

We currently support
https://.apps..altinn.no/ttd/**/#**/instance/
and
https://.apps..altinn.no/ttd/**#**/instance/

This is a point of confusion, e.g. when creating a integration test which checks that the routing is as expected.

### Additional Information

_No response_

### Tasks

_No response_

### Acceptance Criterias

_No response_

No file, test, or entry point is named. Start by locating the app URL and routing configuration in this repository, compare handling of URLs with and without the slash before the fragment, and confirm which single form should be supported. Done means routing behavior and its integration coverage consistently enforce that form.

Written by the indexing model from the issue text.