RHOAIENG-58422: Hide welcome prompt when real messages exist in Playground chat

The ChatbotWelcomePrompt was rendered unconditionally when showWelcomePrompt
was true, causing placeholder messages to remain visible alongside real user
and assistant messages. This adds a check on the message count so the welcome
prompt is only shown when there are no real messages (at most the initial bot
placeholder).

Closes RHOAIENG-58422

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Nick Gagan <ngagan@redhat.com>

Author: jira-autofix-bot

packages/gen-ai/frontend/src/app/Chatbot/ChatbotConfigInstance.tsx

@@ -136,7 +136,7 @@ export const ChatbotConfigInstance: React.FC<ChatbotConfigInstanceProps> = ({
 
   return (
     <MessageBox position="top">
-      {showWelcomePrompt && (
+      {showWelcomePrompt && messagesHook.messages.length <= 1 && (
         <ChatbotWelcomePrompt
           title={username ? `Hello, ${username}` : 'Hello'}
           description={welcomeDescription}

packages/gen-ai/frontend/src/app/Chatbot/__tests__/ChatbotConfigInstance.spec.tsx

@@ -1,23 +1,29 @@
 import * as React from 'react';
-import { act, render } from '@testing-library/react';
+import { act, render, screen } from '@testing-library/react';
 import { useChatbotConfigStore } from '~/app/Chatbot/store/useChatbotConfigStore';
 import { DEFAULT_CONFIGURATION } from '~/app/Chatbot/store/types';
 import { DEFAULT_CONFIG_ID } from '~/app/Chatbot/store';
 import { ChatbotConfigInstance } from '~/app/Chatbot/ChatbotConfigInstance';
 
 jest.mock('@patternfly/chatbot', () => ({
   MessageBox: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
-  ChatbotWelcomePrompt: () => null,
+  ChatbotWelcomePrompt: (props: Record<string, unknown>) => (
+    <div data-testid={props['data-testid']}>Welcome</div>
+  ),
 }));
 
 jest.mock('~/app/Chatbot/ChatbotMessagesList', () => ({
   ChatbotMessages: () => null,
 }));
 
+let mockMessages: unknown[] = [];
+
 jest.mock('~/app/Chatbot/hooks/useChatbotMessages', () => ({
   __esModule: true,
   default: () => ({
-    messages: [],
+    get messages() {
+      return mockMessages;
+    },
     isLoading: false,
     isStreamingWithoutContent: false,
     modelDisplayName: '',
@@ -117,4 +123,31 @@ describe('ChatbotConfigInstance', () => {
       ).toBe('vs-inline-new');
     });
   });
+
+  describe('welcome prompt visibility', () => {
+    beforeEach(() => {
+      mockMessages = [];
+    });
+
+    it('should show welcome prompt when showWelcomePrompt is true and no real messages exist', () => {
+      mockMessages = [{ id: '1', role: 'bot', content: 'placeholder' }];
+      render(<ChatbotConfigInstance {...defaultProps} showWelcomePrompt />);
+      expect(screen.getByTestId('chatbot-welcome-prompt')).toBeInTheDocument();
+    });
+
+    it('should hide welcome prompt when real messages exist', () => {
+      mockMessages = [
+        { id: '1', role: 'bot', content: 'placeholder' },
+        { id: '2', role: 'user', content: 'Hello' },
+      ];
+      render(<ChatbotConfigInstance {...defaultProps} showWelcomePrompt />);
+      expect(screen.queryByTestId('chatbot-welcome-prompt')).not.toBeInTheDocument();
+    });
+
+    it('should not show welcome prompt when showWelcomePrompt is false', () => {
+      mockMessages = [];
+      render(<ChatbotConfigInstance {...defaultProps} showWelcomePrompt={false} />);
+      expect(screen.queryByTestId('chatbot-welcome-prompt')).not.toBeInTheDocument();
+    });
+  });
 });