Upload purger goroutine never exits

Description

In handlers.NewApp() there is a call to startUploadPurger, which creates a background goroutine to call storage.PurgeUploads. The goroutine runs forever and there's no way to interrupt it, so it leaks when you call (app *App) Shutdown().

Seems like the shutdown should also stop and background threads that the app starts.

Reproduce

Observed in internal unit tests.

app := handlers.NewApp(...)
app.Shutdown()

/// purge upload still running

Expected behavior

No response

registry version

v3.0.0

Additional Info

No response