Refactor TestReportSummary with total

Ref: #223240 (closed)

What does this MR do?

This MR refactors our TestReportSummary API.

It includes the following items:

• Refactor TestReportSummaryEntity to expose all counter data through a new hash
• Rename some variables to better express what the actual data is
• Get rid of useless attr_accessor not being used outside of the class

This MR does not implement this refactor for a TestSuiteSummary, this will be tackled in a follow up MR

Why are we doing this?

We want to unify our data structure returned by our API. This way we encapsulate everything within a new total hash to simplify our codebase.

Screenshots

Endpoint	JSON response
Before
After

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