Kaoski/MM-56819 mmctl user preference local mode support

[kaoski]

Summary

This commit introduces support for --local mode in MMCTL for managing user preferences. The following changes have been added:

1. API endpoints for user preferences are registered with the local router.
2. Test cases have been added to ensure functionality for both System Admins and --local mode.

Note: As there is no authentication/authorization required in --local mode, @mattermod suggested omitting session checks from the API handlers. But we are already bypassing session checks for local mode requests as detailed here. Hence, I have retained the existing session checks in place.

Ticket Link

Github Issue: #26864
Jira Ticket: https://mattermost.atlassian.net/browse/MM-56819

Release Note

1. Added --local mode support in MMCTL to handle user preferences.

[mm-cloud-bot]

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[mattermost-build]

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