[SPARK-51577] Make gradle build to automatically append SNAPSHOT suffix to version for non-release builds

What changes were proposed in this pull request?
This PR makes gradle build automatically append -SNAPSHOT suffix to version for non-release builds

Why are the changes needed?
This would help to reduce one duplicate hard-coded version in gradle scripts, as we already defined version in gradle properties

Does this PR introduce any user-facing change?
No

How was this patch tested?
pass the CIs

Was this patch authored or co-authored using generative AI tooling?
No

Author: jiangzho

build.gradle

@@ -34,8 +34,9 @@ assert JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_17): "Java 17
 
 allprojects {
   group = "org.apache.spark.k8s.operator"
-  version = "0.1.0-SNAPSHOT"
-}
+  if (!project.hasProperty('release')) {
+    version += "-SNAPSHOT"
+  }}
 
 tasks.register('buildDockerImage', Exec) {
   String cmd = "docker build --build-arg APP_VERSION=${version} -t spark-kubernetes-operator:${version} -f build-tools/docker/Dockerfile ."