Keep dependency repository definitions well defined

hibernate-core/hibernate-core.gradle

@@ -10,10 +10,6 @@ plugins {
     id 'org.hibernate.build.xjc-jakarta'
 }
 
-repositories {
-    gradlePluginPortal()
-}
-
 description = 'Hibernate\'s core ORM functionality'
 
 apply from: rootProject.file( 'gradle/published-java-module.gradle' )

settings.gradle

@@ -30,6 +30,7 @@ dependencyResolutionManagement {
             url( rootProject.property( "mavenMirror" ) )
         }
         mavenCentral()
+        if (System.env['JPA_PREVIEW'] != null) {
             // Needed for the RC versions of Jakarta Persistence
             maven {
                 url "https://jakarta.oss.sonatype.org/content/repositories/releases/"
@@ -38,6 +39,7 @@ dependencyResolutionManagement {
             maven {
                 url "https://jakarta.oss.sonatype.org/content/repositories/snapshots/"
             }
+        }
 
         //Allow loading additional dependencies from a local path;
         //useful to load JDBC drivers which can not be distributed in public.