Extend GraphQL Ci::PipelineType to include Security Report Findings

What does this MR do?

Backend work to update the pipeline security tab to use GraphQL

• Create new PipelineSecurityReportFindingType GraphQL Type to be used by Ci::Pipeline
• Create new GraphQL PipelineSecurityReportFindingsResolver
• Add ability to filter by scanner, severity and reportType

We need to add more fields for finding type as required by ui implementation later but basic structure is here.

Screenshots (strongly suggested)

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 #298760 (closed)