Grafana Investigation: Sidebars "timeline" and "comparison" do not handle subpath correctly

### What happened? After opening an investigation, if I want to open either: - "Compare time ranges..." - "Open timeline" My subpath "/grafana" is not taken into account, leading to a 404. Click on "Compare time ranges..." **Not working**: https://xxxx/a/grafana-investigations-app/comparison?investigationID=0f59b404-9e79-4e68-a276-638b162489e2&context=page&from=2025-11-27T08%3A33%3A10.879Z&to=2025-11-27T09%3A33%3A10.879Z **Working**: https://xxxx/grafana/a/grafana-investigations-app/comparison?investigationID=0f59b404-9e79-4e68-a276-638b162489e2&context=page&from=2025-11-27T08%3A33%3A10.879Z&to=2025-11-27T09%3A33%3A10.879Z Click on "Open timeline..." **Not working**: https://xxxx/grafana//grafana/a/grafana-investigations-app/timeline?investigationID=0f59b404-9e79-4e68-a276-638b162489e2&context=page **Working**: https://xxxx/grafana/a/grafana-investigations-app/timeline?investigationID=0f59b404-9e79-4e68-a276-638b162489e2&context=page Moreover I have 2 others 404 errors, in the dev tools, here are the URLs: https://xxxx/grafana/apis/investigations.grafana.app/v0alpha1/namespaces/org-2/investigations?limit=1 https://xxxx/grafana/apis/investigations.grafana.app/v0alpha1/namespaces/org-2/investigationindexes?limit=1 <img width="223" height="212" alt="Image" src="https://github.com/user-attachments/assets/56aa7d6e-9008-4dc2-ba05-4a8d3b1c1cc5" /> ### What did you expect to happen? No error and subpath to work. ### Did this work before? No ### How do we reproduce it? 1. As describe above ### Is the bug inside a dashboard panel? No in "investigations app". ### Environment (with versions)? Grafana: 12.3.0 OS: Linux Browser: Chrome ### Grafana platform? Kubernetes ### Datasource(s)? Loki and Prometheus