Add --local mode support to MMCTL for user preferences

[mattermod]

Recently a feature was added to MMCTL for user preferences so that you can list this data and manipulate it. https://github.com/mattermost/mattermost/pull/25721

This feature does not yet work when using MMCTL in --local mode.
It would make sense to implement this for local mode as well and maintain feature parity. To enable this feature to work with the local mode, we need to register these API endpoints to the local router. Similar to what has been done here: https://github.com/mattermost/mattermost/blob/master/server/channels/api4/user_local.go

Since there is no authentication/authorization in local mode, the API handlers needs to be stripped from session checks: https://github.com/mattermost/mattermost/blob/master/server/channels/api4/preference.go

Lastly the https://github.com/mattermost/mattermost/blob/master/server/channels/api4/preference_test.go file needs to be updated to test local mode. It can be achieved by using TestForSystemAdminAndLocal utility implemented here: https://github.com/mattermost/mattermost/blob/master/server/channels/api4/apitestlib.go#L982 .

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JIRA: https://mattermost.atlassian.net/browse/MM-56819

[kaoski]

@mattermod @amyblais Can I work on this issue?

[kaoski]

Have a query from the issue description

Since there is no authentication/authorization in local mode, the API handlers needs to be stripped from session checks: https://github.com/mattermost/mattermost/blob/master/server/channels/api4/preference.go

@mattermod @amyblais We are already skipping session checks for requests from local mode here . Why we should explicitly remove session checks from the local handler here?

[amyblais]

Have a query from the issue description

Since there is no authentication/authorization in local mode, the API handlers needs to be stripped from session checks: https://github.com/mattermost/mattermost/blob/master/server/channels/api4/preference.go

We are already skipping session checks for requests from local mode here . Why we should explicitly remove session checks from the local handler here?

cc @isacikgoz

[kaoski]

PR: #26972
cc: @amyblais