Add missing fields to Alert Details view

What does this MR do?

This MR adds missing fields to the Alert Details view.

• description
• updatedAt
• details

It also tidies up the graphql queries to make better use of fragments. This changes the order of the results on the page, but since it was already unordered this is ok. I've asked UX here #214550 (comment 344068623) if we want to define an order for these fields.

Issue: #214550 (closed)

Screenshots

before	after

Does this MR meet the acceptance criteria?

Conformity

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

Availability and Testing

• [n/a] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• [n/a] 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:

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