UserStore migration (#15563)

* Migration completed

* Fix tests

* Fix tests

* Fix tests

* Suggestions

* Trigger CI

* Suggestions

* Merge with master

* Trigger CI

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Agniva De Sarker <agnivade@yahoo.co.in>

app/permissions.go

@@ -30,7 +30,7 @@ func (a *App) ResetPermissionsSystem() *model.AppError {
 
 	// Reset all Custom Role assignments to Users.
 	if err := a.Srv().Store.User().ClearAllCustomRoleAssignments(); err != nil {
-		return err
+		return model.NewAppError("ResetPermissionsSystem", "app.user.clear_all_custom_role_assignments.select.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
 	// Reset all Custom Role assignments to TeamMembers.