Use LookAhead to preload queries for RequirementType

Some fields on RequirementType are marked with complexity: 5 because they perform N+1 queries.

We can now remove the N+1 using LookAhead to preload objects.

Fields:

field :last_test_report_state, RequirementsManagement::TestReportStateEnum, null: true, complexity: 5
field :last_test_report_manually_created,
            GraphQL::BOOLEAN_TYPE,
            method: :last_test_report_manually_created?,
            null: true,
            complexity: 5