Follow-up from "Use only uuid to pick correct finding from the reports"

The following discussion from !55643 (merged) should be addressed:

• @10io started a discussion:

  Thoughts for a follow up:

  I see several specs examples using :finding1 and :finding2 as let! variables.

  We could imagine grouping those examples in a single context where :finding1 and :finding2 are let_it_be variables

Implementation plan

• backend Currently we are creating finding records for each context in ee/spec/models/security/finding_spec.rb. We can create top-level finding records with let_it_be helper to improve the performance of this test.