[QPOv2] Add N active jobs and clear queue button (#7731)

Add text displaying N active jobs and a clear queue button to the media
assets sidebar tab.

<img width="824" height="208" alt="image"
src="https://github.com/user-attachments/assets/6996251a-8d2c-4527-ba1c-26f450859236"
/>

Part of the QPO v2 iteration, figma design can be found
[here](https://www.figma.com/design/LVilZgHGk5RwWOkVN6yCEK/Queue-Progress-Modal?node-id=3330-37286&m=dev).
This will be implemented in a series of stacked PRs that can be reviewed
and merged individually.

main <-- #7731, #7737, #7743, #7745

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7731-QPOv2-Add-N-active-jobs-and-clear-queue-button-2d16d73d365081468c1ce8f9d1b9a0c1)
by [Unito](https://www.unito.io)

src/locales/en/main.json

@@ -738,6 +738,7 @@
       "filterCurrentWorkflow": "Current workflow",
       "sortJobs": "Sort jobs",
       "sortBy": "Sort by",
+      "activeJobs": "{count} active job | {count} active jobs",
       "activeJobsSuffix": "active jobs",
       "jobQueue": "Job Queue",
       "expandCollapsedQueue": "Expand job queue",