pre-build in CI

Author: samfreund

.github/workflows/build.yml

@@ -91,6 +91,8 @@ jobs:
         run: |
           pnpm install
           pnpm exec playwright install --with-deps
+      - name: Prebuild Gradle
+        run: ./gradlew photon-targeting:build photon-core:build photon-server:build -x check
       - name: Run Playwright tests
         working-directory: photon-client
         run: pnpm exec playwright test