Draft: Update Secure and Protect empty states

What does this MR do?

Updates per #289295 (closed), to align empty state on Secure/Protect feature pages. Updates include:

• Align call-to-action button to "Learn more about <feature name>"
• Update call-to-action button to be info-blue (btn-primary) (remove buttons per #289295 (comment 457574448))
• Add More information end of sub-text anchoring to documentation
• Add page for Vulnerability Report empty state (both sec-dashboard and new vuln report point to same empty state)
• Update some descriptions (TBD per copy writer review)

Screenshots (strongly suggested)

Align call-to-action button to "Learn more about <feature name>"

Threat monitoring	Security dashboard

In progress: Update call-to-action button to be info-blue (btn-primary)

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

Related to #289295 (closed)