Feature request (dashboard): Prompt user to save dashboard layouts prior to navigating away

[Sriram-bk]

Feature request

Is your feature request related to a problem?

When a user is in the Dashboard layout edit view and proceeds to edit an insight after rearranging insight panels, the new layout doesn't get saved.

Describe the solution you'd like

Save the layout automatically or prompt the user to save or discard the new layout prior to navigating away.

Describe alternatives you've considered

Additional context

From : https://posthoghelp.zendesk.com/agent/tickets/26761

Debug info

- [ ] PostHog Cloud, Debug information: [please copy/paste from https://us.posthog.com/settings/project-details#variables]
- [ ] PostHog Hobby self-hosted with `docker compose`, version/commit: [please provide]
- [ ] PostHog self-hosted with Kubernetes (deprecated, see [`Sunsetting Kubernetes support`](https://posthog.com/blog/sunsetting-helm-support-posthog)), version/commit: [please provide]