Refactor GraalVM setup in build.sh

Author: diegomarquezp

.kokoro/build.sh

@@ -72,8 +72,11 @@ integration)
     ;;
 graalvm)
     # Run Unit and Integration Tests with Native Image
-    curl -s "https://get.sdkman.io" | bash
-    sdk install java 25-graalce
+    set -ex
+    microdnf install zip
+    curl -s "https://get.sdkman.io" | bash -e
+    source "/root/.sdkman/bin/sdkman-init.sh"
+    sdk install java 25-graalce -Y
     java -version
     mvn -B ${INTEGRATION_TEST_ARGS} -ntp -Pnative -Penable-integration-tests test
     RETURN_CODE=$?