Prevent DAST profiles from being deleted when referenced by policies

What does this MR do?

This change adds new fields to GraphQL API and adds additional constraint that verifies if given DAST Site/Scanner profile can be deleted if is referenced by active policy

Implementation Issue

Related to #321632 (closed)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry

Not needed:

Any change behind a disabled feature flag should not have a changelog entry.

• Documentation (if required)
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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