Revert back to Gradle 8.14.3

Something in Gradle 9 broke the assemble workflow such that the tarballs
are not being generated. This is a minimal revert of opensearch-project#19329 to go back
to using Gradle 8.14.3 which fixes the assemble workflow.

Signed-off-by: Andrew Ross <[email protected]>

Author: andrross

buildSrc/build.gradle

@@ -130,7 +130,7 @@ dependencies {
   testFixturesApi gradleTestKit()
   testImplementation 'org.wiremock:wiremock-standalone:3.6.0'
   testImplementation "org.mockito:mockito-core:${props.getProperty('mockito')}"
-  integTestImplementation('org.spockframework:spock-core:2.4-M6-groovy-4.0') {
+  integTestImplementation('org.spockframework:spock-core:2.3-groovy-3.0') {
     exclude module: "groovy"
   }
 }

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
 

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.1.0-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.3-all.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME