Fix Reports nav underline (#43137)

<!-- Add the related story/sub-task/bug number, like Resolves #123, or
remove if NA -->
**Related issue:** Resolves #43125

# Checklist for submitter

- [x] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
See [Changes
files](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/guides/committing-changes.md#changes-files)
for more information.

## Testing

- [x] QA'd all new/changed functionality manually

<img width="2116" height="553" alt="Screenshot 2026-04-07 at 1 38 06 PM"
src="https://github.com/user-attachments/assets/62b58312-9fed-4a59-bc0b-bdf0aeaf8e3a"
/>

changes/43125-reports-nav-underline

@@ -0,0 +1 @@
+* Fixed missing underline on "Reports" nav item when active in top navigation.

frontend/components/top_nav/SiteTopNav/navItems.ts

@@ -85,7 +85,7 @@ export default (
     {
       name: "Reports",
       location: {
-        regex: new RegExp(`^${URL_PREFIX}/queries/`),
+        regex: new RegExp(`^${URL_PREFIX}/reports/`),
         pathname: PATHS.MANAGE_REPORTS,
       },
       withParams: { type: "query", names: ["fleet_id"] },