ci: remove android-actions/setup-android, use preinstalled SDK

The action consistently fails trying to re-download cmdline-tools
from Google CDN (corrupt zip). The ubuntu-latest runner already ships
a working Android SDK at $ANDROID_HOME — call sdkmanager directly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/build-android.yml

@@ -42,15 +42,13 @@ jobs:
       - name: Install dependencies
         run: npm ci
 
-      - name: Set up Android SDK
-        uses: android-actions/setup-android@v3
-
       - name: Accept Android SDK licenses
-        run: yes | sdkmanager --licenses || true
+        run: yes | "$ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager" --licenses || true
 
       - name: Install SDK components
         run: |
-          sdkmanager "platform-tools" "platforms;android-35" "build-tools;35.0.0"
+          "$ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager" \
+            "platform-tools" "platforms;android-35" "build-tools;35.0.0"
 
       - name: Cache Gradle
         uses: actions/cache@v4