release.ps1: keep Gradle's warnings from stopping a piped run

Gradle prints compiler warnings on its error stream. When the script's output was piped or
sent to a file, PowerShell 5.1 took the first such line for an error and stopped the build
at step 2 (seen on the first 0.3.1 attempt). The streams are now merged inside cmd, and
only the exit code decides whether the build failed.

Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>

flexera/release.ps1

@@ -170,7 +170,10 @@ if ($SkipBuild) {
     Get-ChildItem (Join-Path $Root 'build\kotlin') -Directory -Filter "compile${Variant}Kotlin*" -ErrorAction SilentlyContinue |
         Remove-Item -Recurse -Force
     $env:JAVA_HOME = $JavaHome
-    cmd /c ".\gradlew.bat assemble$Variant --no-build-cache --console=plain"
+    # "2>&1" inside cmd: Gradle prints compiler warnings on its error stream. If this script's
+    # output is piped or sent to a file, PowerShell would otherwise take the first such line
+    # for an error and stop the build. Only the exit code says whether the build failed.
+    cmd /c ".\gradlew.bat assemble$Variant --no-build-cache --console=plain 2>&1"
     if ($LASTEXITCODE -ne 0) { throw "The build failed." }
 }
 if (-not (Test-Path $apk)) { throw "Expected the APK at $apk, but it is not there." }