Add new illustrations to product analytics onboarding flow

What does this MR do and why?

Add new illustrations to product analytics onboarding flow

New illustrations "cloud-tanuki" and "cloud-user" added to the provider selection cards within the product analytics onboarding flow.

Also uses new illustrations for loading state once onboarding has started (removes the old non-compliant chart illustration).

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Before	After
	(Small viewport, illustrations hide)
	(Creating on GitLab-managed provider)
	(Creating on self-managed provider)
	(Leaving onboarding page after starting create instance, and returning before instance created)*

* Note this is a bit of an edge case where if you start creating instance, leave the onboarding page, and come back before the instance has finished creating (which usually only takes some seconds) the component has lost the context of which provider is being onboarded (since our onboarding state just says "creating instance" with no further details). So in this case, we do not show any illustration on the loading page. I think this is OK given how edge case it is to actually get into this situation.

How to set up and validate locally

1. Follow these instructions to setup Product Analytics in GDK.
2. echo "Feature.enable(:product_analytics_byoc)" | gdk rails c and run as .com
3. View the onboarding page for a new project at Project > Analytics > Analytics dashboards > Set Up [product analytics].
4. Verify new onboarding page displays illustrations as expected
5. Select providers, verify loading state displays new illustrations as expected

Related to #454379