Set Gradle warning mode back to fail (opensearch-project#20390)

The protobuf gradle plugin has been updated to remove the gradle warning
so we can change back to fail on gradle warnings. Also change the protobuf
gradle plugin to use a specific version to make the build more reproducible.

Signed-off-by: Andrew Ross <andrross@amazon.com>

Author: andrross

gradle.properties

@@ -26,10 +26,7 @@ options.forkOptions.memoryMaximumSize=3g
 systemProp.org.gradle.dependency.duplicate.project.detection=false
 
 # Enforce the build to fail on deprecated gradle api usage
-# TODO: Waiting for https://github.com/google/protobuf-gradle-plugin/commit/894f2d25e2b511bc11661f4d23e47ee0671e82ad
-# to be released in the Protobuf gradle plugin, at which this point can be changed
-# back to `fail`
-systemProp.org.gradle.warning.mode=all
+systemProp.org.gradle.warning.mode=fail
 
 systemProp.jdk.tls.client.protocols=TLSv1.2,TLSv1.3
 

server/build.gradle

@@ -31,7 +31,7 @@
 import groovy.xml.XmlParser
 
 plugins {
-  id('com.google.protobuf') version 'latest.release'
+  id('com.google.protobuf') version '0.9.6'
   id('opensearch.build')
   id('opensearch.publish')
   id('opensearch.internal-cluster-test')