Add EuiAvatar playground story

src/components/avatar/avatar.stories.tsx

@@ -0,0 +1,40 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import type { Meta, StoryObj } from '@storybook/react';
+
+import { EuiAvatar, EuiAvatarProps } from './avatar';
+
+const meta: Meta<EuiAvatarProps> = {
+  title: 'EuiAvatar',
+  component: EuiAvatar,
+  argTypes: {
+    initialsLength: {
+      options: [undefined, 1, 2],
+    },
+    color: { control: 'text' },
+    iconType: { control: 'text' },
+    iconColor: { control: 'text' },
+  },
+  args: {
+    // Component defaults
+    casing: 'uppercase',
+    size: 'm',
+    type: 'user',
+    isDisabled: false,
+  },
+};
+
+export default meta;
+type Story = StoryObj<EuiAvatarProps>;
+
+export const Playground: Story = {
+  args: {
+    name: 'Hello World',
+  },
+};