don't build release builds in CI, because it wants to upload to crashlytics

.github/workflows/android.yml

@@ -38,7 +38,5 @@ jobs:
       uses: actions/setup-java@master
       with:
         java-version: 1.8
-    - name: Build java code
-      run: bash ./gradlew build
     - name: Unit tests
       run: bash ./gradlew test --stacktrace