How to use the @theia/workspace/lib/browser.WorkspaceCommands.NEW_FILE function in @theia/workspace

async registerToolbarItems(toolbarRegistry: TabBarToolbarRegistry): Promise {
        toolbarRegistry.registerItem({
            id: FileNavigatorCommands.REFRESH_NAVIGATOR.id,
            command: FileNavigatorCommands.REFRESH_NAVIGATOR.id,
            tooltip: 'Refresh Explorer',
            priority: 0,
        });
        toolbarRegistry.registerItem({
            id: FileNavigatorCommands.COLLAPSE_ALL.id,
            command: FileNavigatorCommands.COLLAPSE_ALL.id,
            tooltip: 'Collapse All',
            priority: 1,
        });
        this.registerMoreToolbarItem({
            id: WorkspaceCommands.NEW_FILE.id,
            command: WorkspaceCommands.NEW_FILE.id,
            tooltip: WorkspaceCommands.NEW_FILE.label,
            group: NavigatorMoreToolbarGroups.NEW_OPEN,
        });
        this.registerMoreToolbarItem({
            id: WorkspaceCommands.NEW_FOLDER.id,
            command: WorkspaceCommands.NEW_FOLDER.id,
            tooltip: WorkspaceCommands.NEW_FOLDER.label,
            group: NavigatorMoreToolbarGroups.NEW_OPEN,
        });
        this.registerMoreToolbarItem({
            id: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.id,
            command: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.id,
            tooltip: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.label,
            group: NavigatorMoreToolbarGroups.TOOLS,
        });

async registerToolbarItems(toolbarRegistry: TabBarToolbarRegistry): Promise {
        toolbarRegistry.registerItem({
            id: FileNavigatorCommands.REFRESH_NAVIGATOR.id,
            command: FileNavigatorCommands.REFRESH_NAVIGATOR.id,
            tooltip: 'Refresh Explorer',
            priority: 0,
        });
        toolbarRegistry.registerItem({
            id: FileNavigatorCommands.COLLAPSE_ALL.id,
            command: FileNavigatorCommands.COLLAPSE_ALL.id,
            tooltip: 'Collapse All',
            priority: 1,
        });
        this.registerMoreToolbarItem({
            id: WorkspaceCommands.NEW_FILE.id,
            command: WorkspaceCommands.NEW_FILE.id,
            tooltip: WorkspaceCommands.NEW_FILE.label,
            group: NavigatorMoreToolbarGroups.NEW_OPEN,
        });
        this.registerMoreToolbarItem({
            id: WorkspaceCommands.NEW_FOLDER.id,
            command: WorkspaceCommands.NEW_FOLDER.id,
            tooltip: WorkspaceCommands.NEW_FOLDER.label,
            group: NavigatorMoreToolbarGroups.NEW_OPEN,
        });
        this.registerMoreToolbarItem({
            id: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.id,
            command: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.id,
            tooltip: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.label,
            group: NavigatorMoreToolbarGroups.TOOLS,
        });
        this.registerMoreToolbarItem({