Discourse doesn't limit reviewable user serializer payload

Vulnerability Description

Discourse is an open-source discussion platform. Prior to version 3.2.3 on the `stable` branch and version 3.3.0.beta4 on the `beta` and `tests-passed` branches, moderators using the review queue to review users may see a users email address even when the Allow moderators to view email addresses setting is disabled. This issue is patched in version 3.2.3 on the `stable` branch and version 3.3.0.beta4 on the `beta` and `tests-passed` branches. As possible workarounds, either prevent moderators from accessing the review queue or disable the approve suspect users site setting and the must approve users site setting to prevent users from being added to the review queue.

References

• https://github.com/discourse/discourse/security/advisories/GHSA-rr93-hcw4-cv3f
• https://github.com/discourse/discourse/commit/8d5b21170efa4766e1a213ff07dc36d36cf3dfb4
• https://github.com/discourse/discourse/commit/e2a7265dba3d9e943338db21ca38c50276b22f47