Pull Request resolves #46338

• I read the Generative AI policy and my contribution is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

This PR refactors the rendering of update messages in the Upload & Update view.

Previously:

• The generic update instruction and direct update package message were rendered in a way that caused duplication and inconsistent UI.
• Messages could appear multiple times or in separate alert blocks, leading to confusion.

Changes made:

• Consolidated both messages into a single alert container.
• Always display the generic update instruction message.
• Conditionally display the direct download message only when update data is available.
• Removed redundant and duplicate rendering paths.

This improves UI clarity, avoids repetition, and maintains both functional use cases.

Testing Instructions

1. Navigate to:
   Administrator → System → Joomla Update → Upload & Update

2. Test two scenarios:

   Case 1: Update available

   • Ensure both messages are displayed inside a single alert box:
     • Generic instruction message
     • Direct update package message

   Case 2: No update available (simulated)

   • Temporarily set:

     $hasUpdate = false;

   • Verify that only the generic instruction message is displayed.

3. Ensure:

   • No duplicate messages appear
   • Only one alert container is rendered
   • Layout remains clean and consistent

Actual result BEFORE applying this Pull Request

• Multiple alert boxes were displayed
• Duplicate or repeated messages appeared
• UI was cluttered and confusing

Expected result AFTER applying this Pull Request

• A single alert box is displayed
• Messages are clearly structured and non-duplicated
• Direct download message appears only when update data is available
• Improved readability and user experience

Screenshots / Testing Evidence

Before Fix (Duplicate / inconsistent messages):
https://github.com/user-attachments/assets/9bf8500b-b59c-4ddf-bcd4-59802e0df3e7

After Fix (Single alert, clean UI, no duplication):