Fix flaky and quarantined abuse_report_details_entity_spec.rb

What does this MR do and why?

Reload records user and report to prevent state leakage between example groups.

Closes #441135 (closed).

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

bin/rspec ./ee/spec/serializers/ee/admin/abuse_report_details_entity_spec.rb[1:2:1:1,1:2:2:1] --seed 28415
while :; do bin/rspec ./ee/spec/serializers/ee/admin/abuse_report_details_entity_spec.rb || break; done