We were incorrectly excluding deactivated users
while getting channel members for a DM channel, whereas
we were actually exporting all users in the users array.
We fix this and also correctly honor the includeArchivedChannels
flag as well.
https://mattermost.atlassian.net/browse/MM-55524
```release-note
Include deactivated members in a favorited DM channel export.
```
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Co-authored-by: Mattermost Build <build@mattermost.com>