Add library build task to Android test CI workflow

Author: thunderbiscuit

.github/workflows/test-android.yaml

@@ -52,6 +52,11 @@ jobs:
       - name: "Install Rust Android targets"
         run: rustup target add x86_64-linux-android aarch64-linux-android armv7-linux-androideabi
 
+      - name: "Build Android library"
+        run: |
+          cd bdk-android
+          ./gradlew buildAndroidLib
+
 # There are currently no unit tests for bdk-android and the integration tests require the macOS image
 # which is not working with the older NDK version we are using, so for now we just make sure that the library builds.
 #      - name: "Run Android unit tests"