Gutenberg: remove remaining usages of wordpress/nux package

We don't use core guided tour in Calypso so we don't need the DotTip
component from this package. Since this is the last remaining usage,
I'm cleaning up the whole packge so we don't have to worry about it
in future renovate updates.

client/gutenberg/editor/edit-post/components/header/index.js

@@ -13,7 +13,6 @@ import { IconButton } from '@wordpress/components';
 import { PostPreviewButton, PostSavedState } from '@wordpress/editor';
 import { withDispatch, withSelect } from '@wordpress/data';
 import { compose } from '@wordpress/compose';
-import { DotTip } from '@wordpress/nux';
 
 /**
  * Internal dependencies
@@ -32,6 +31,7 @@ function Header( {
 } ) {
 	const toggleGeneralSidebar = isEditorSidebarOpened ? closeGeneralSidebar : openGeneralSidebar;
 
+	/* eslint-disable wpcalypso/jsx-classname-namespace */
 	return (
 		<div
 			role="region"
@@ -55,18 +55,14 @@ function Header( {
 							aria-expanded={ isEditorSidebarOpened }
 							shortcut={ shortcuts.toggleSidebar }
 						/>
-						<DotTip tipId="core/editor.settings">
-							{ __(
-								'You’ll find more settings for your page and blocks in the sidebar. Click “Settings” to open it.'
-							) }
-						</DotTip>
 					</div>
 					<PinnedPlugins.Slot />
 					<MoreMenu />
 				</div>
 			) }
 		</div>
 	);
+	/* eslint-enable wpcalypso/jsx-classname-namespace */
 }
 
 export default compose(

package.json

@@ -51,7 +51,6 @@
     "@wordpress/hooks": "2.0.3",
     "@wordpress/i18n": "3.0.1",
     "@wordpress/keycodes": "2.0.3",
-    "@wordpress/nux": "2.0.9",
     "@wordpress/plugins": "2.0.6",
     "@wordpress/rich-text": "2.0.2",
     "@wordpress/url": "2.2.0",