MM-44101: GraphQL: Add sidebar categories at the top level (#20178)

Also, add a negate parameter to the team members to get
all sidebarcategories except the default team.

```release-note
NONE
```

app/import_functions.go

@@ -737,7 +737,7 @@ func (a *App) importUserTeams(user *model.User, data *[]UserTeamImportData) *mod
 	isGuestByTeamId := map[string]bool{}
 	isUserByTeamId := map[string]bool{}
 	isAdminByTeamId := map[string]bool{}
-	existingMemberships, nErr := a.Srv().Store.Team().GetTeamsForUser(context.Background(), user.Id, true)
+	existingMemberships, nErr := a.Srv().Store.Team().GetTeamsForUser(context.Background(), user.Id, "", true)
 	if nErr != nil {
 		return model.NewAppError("importUserTeams", "app.team.get_members.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 	}