MM-57824: Export/import custom status (#27361)

https://mattermost.atlassian.net/browse/MM-57824
```release-note
NONE
```

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/imports/import_types.go

@@ -85,7 +85,8 @@ type UserImportData struct {
 	TutorialStep        *string `json:"tutorial_step,omitempty"`
 	EmailInterval       *string `json:"email_interval,omitempty"`
 
-	NotifyProps *UserNotifyPropsImportData `json:"notify_props,omitempty"`
+	NotifyProps  *UserNotifyPropsImportData `json:"notify_props,omitempty"`
+	CustomStatus *model.CustomStatus        `json:"custom_status,omitempty"`
 }
 
 type UserNotifyPropsImportData struct {