Blocked users in group's members for Merge Request approvers

Summary

When a group is added to a merge request approvers users that are blocked (but still members of the group) still show up in list of approvers.

Steps to reproduce

1. Create a project within a group and populate with branches
2. Update merge request approvers with parent group
3. Create Merge request / Review users

Any blocked users before the MR was created or users blocked afterward will be visible.

What is the current bug behavior?

Blocked users displayed as potential approvers

What is the expected correct behavior?

Only valid users should be displayed.

Reproduced on 11.8.2

Internal ZD