[Storybook] Use native theme switcher (#215443)

## Summary

Closes #213294

This PR replaces the custom theme switcher in favor of the native
toolbar customization SB has integrated.

Also removed `@storybook/icons` which was only used in the theme
switcher component.

## How to test
1. Run `yarn storybook <plugin>`
2. You should be able to change between themes on the toolbar.

Author: rmyz

package.json

@@ -1572,7 +1572,6 @@
     "@storybook/components": "^8.6.3",
     "@storybook/core-events": "^8.6.3",
     "@storybook/core-server": "^8.6.3",
-    "@storybook/icons": "^1.3.2",
     "@storybook/manager-api": "^8.6.3",
     "@storybook/preview-api": "^8.6.3",
     "@storybook/react": "^8.6.3",

src/platform/packages/shared/kbn-storybook/src/lib/preview.ts

@@ -10,13 +10,53 @@
 import type { Preview } from '@storybook/react';
 import * as jest from 'jest-mock';
 import { decorators } from './decorators';
+import {
+  AMSTERDAM_DARK,
+  AMSTERDAM_LIGHT,
+  BOREALIS_DARK,
+  BOREALIS_LIGHT,
+  DEFAULT_THEME,
+  THEME_TITLES,
+} from './themes';
 
 // @ts-expect-error
 window.jest = jest;
 
 const preview: Preview = {
   decorators,
-  initialGlobals: { euiTheme: 'v8.light' },
+  initialGlobals: { euiTheme: DEFAULT_THEME },
+  globalTypes: {
+    euiTheme: {
+      description: 'Change the EUI theme',
+      toolbar: {
+        title: 'Theme',
+        icon: 'paintbrush',
+        dynamicTitle: true,
+        items: [
+          {
+            value: BOREALIS_LIGHT,
+            icon: 'hearthollow',
+            title: THEME_TITLES[BOREALIS_LIGHT],
+          },
+          {
+            value: BOREALIS_DARK,
+            icon: 'heart',
+            title: THEME_TITLES[BOREALIS_DARK],
+          },
+          {
+            value: AMSTERDAM_LIGHT,
+            icon: 'hearthollow',
+            title: THEME_TITLES[AMSTERDAM_LIGHT],
+          },
+          {
+            value: AMSTERDAM_DARK,
+            icon: 'heart',
+            title: THEME_TITLES[AMSTERDAM_DARK],
+          },
+        ],
+      },
+    },
+  },
 };
 
 // eslint-disable-next-line import/no-default-export

src/platform/packages/shared/kbn-storybook/src/lib/register.ts

@@ -9,7 +9,6 @@
 
 import { addons } from '@storybook/manager-api';
 import { create } from '@storybook/theming';
-import { registerThemeSwitcherAddon } from './register_theme_switcher_addon';
 
 // This configures the "Manager", or main outer view of Storybook. It is an
 // addon that's loaded by the `managerEntries` part of the preset in ../preset.js.
@@ -25,5 +24,3 @@ addons.setConfig({
   panelPosition: 'bottom',
   showToolbar: true,
 });
-
-registerThemeSwitcherAddon();

src/platform/packages/shared/kbn-storybook/src/lib/register_theme_switcher_addon.ts

@@ -10292,7 +10292,7 @@
   resolved "https://registry.yarnpkg.com/@storybook/global/-/global-5.0.0.tgz#b793d34b94f572c1d7d9e0f44fac4e0dbc9572ed"
   integrity sha512-FcOqPAXACP0I3oJ/ws6/rrPT9WGhu915Cg8D02a9YxLo0DE9zI+a9A5gRGvmQ09fiWPukqI8ZAEoQEdWUKMQdQ==
 
-"@storybook/icons@^1.2.12", "@storybook/icons@^1.3.2":
+"@storybook/icons@^1.2.12":
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/@storybook/icons/-/icons-1.3.2.tgz#e9b92c35ca789ff79f9d0b3848829dd6490ca628"
   integrity sha512-t3xcbCKkPvqyef8urBM0j/nP6sKtnlRkVgC+8JTbTAZQjaTmOjes3byEgzs89p4B/K6cJsg9wLW2k3SknLtYJw==