fix(ci): correct GPAC fallback download URL for Windows builds

Fixes build failures when Chocolatey returns 503 errors by correcting
the fallback download URL for GPAC 2.4.

Changes:
- Updated URL from release/2.4.0/ to release/2.4/
- Fixed filename to match actual GPAC 2.4 release artifact
- Verified URL returns 200 OK from official GPAC download server

The previous URL returned 404 because:
1. Directory path used patch version (2.4.0) instead of minor (2.4)
2. Filename had incorrect commit hash

This change maintains all existing logic including the 3-retry
Chocolatey fallback mechanism and silent install parameters.

Author: Rahul-2k4

.github/workflows/build_windows.yml

@@ -59,7 +59,7 @@ jobs:
           # Fallback: Download from GPAC website
           if (-not $chocoSuccess) {
             Write-Host "Chocolatey failed, downloading GPAC directly..."
-            $gpacUrl = "https://download.tsi.telecom-paristech.fr/gpac/release/2.4.0/gpac-2.4.0-rev0-gc05db8ba-master-x64.exe"
+            $gpacUrl = "https://download.tsi.telecom-paristech.fr/gpac/release/2.4/gpac-2.4-rev0-g5d70253a-master-x64.exe"
             $installer = "$env:TEMP\gpac-installer.exe"
             Invoke-WebRequest -Uri $gpacUrl -OutFile $installer -UseBasicParsing
             Start-Process -FilePath $installer -ArgumentList "/S" -Wait