block HTTP redirects for image loading

[usmanvrtx]

Description

This PR blocks HTTP redirects for image loading in the Ensemble Image widget to prevent potential redirect-based attacks (SSRF). A custom RedirectBlockingHttpClient is used both for individual image requests and within the image cache manager.

Related Issue

N/A

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (no functional changes)

What Has Changed

• Added RedirectBlockingHttpClient class that prevents HTTP redirects by setting followRedirects = false and throwing ClientException on 3xx responses
• Updated EnsembleImageCacheManager cache key to ensembleImageCacheKeyNoRedirect to invalidate old cache entries
• Applied errorBuilder callback to cached network images for graceful fallback
• Added httpClient: RedirectBlockingHttpClient() to cached network image requests
• Configured HttpFileService with RedirectBlockingHttpClient in cache manager
• Added unit test for redirect-blocking client behavior

How to Test

1. Run the existing image widget tests: flutter test modules/ensemble/test/widget/image_widget_test.dart
2. Verify the new redirect-blocking test passes
3. Test loading images from URLs that would redirect and confirm they are blocked with a ClientException

Screenshots / Videos

N/A

Checklist

• I have run flutter analyze and addressed any new warnings
• I have run flutter test and all tests pass
• I have tested my changes on the relevant platform(s)
• I have updated documentation if needed
• My changes do not introduce new warnings or errors