Serverless empty state update

What does this MR do?

We have an issue to add an Illustration to our Serverless empty state vue: #25483 (closed)

There is also an issue to update the alignment and border of the vue: gitlab-foss#66628 (closed)

This MR will

• Add serverless illustration to empty state
• Update empty state styles
• Move empty_state props to the store. The empty state props seemed to be passed around to different components. I think that indicates they should be values in the store.
• Update missing_prometheus.vue and functions.vue components to also use new store values instead of prop values
• Updates associated tests

Screenshots

EmptyState

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Closes #25483 (closed)