Minor cleanup and fixing non set distribution type in jdk

Author: breskeby

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/Jdk.java

@@ -115,7 +115,7 @@ public void setArchitecture(final String architecture) {
     }
 
     public String getDistributionVersion() {
-        return distributionVersion.get();
+        return distributionVersion.getOrNull();
     }
 
     public void setDistributionVersion(String distributionVersion) {

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/JdkDownloadPlugin.java

@@ -114,12 +114,8 @@ private void setupRepository(Project project, Jdk jdk) {
                     + jdk.getBuild()
                     + "/[module]/[classifier]/jdk/hotspot/normal/adoptium";
             }
-        } else if (jdk.getVendor().equals(VENDOR_OPENJDK) && jdk.getDistributionVersion().equals("ea")) {
-
-            // "https://builds.es-jdk-archive.com/jdks/openjdk/25/openjdk-25-ea+30/openjdk-25-ea+30_linux-x64_bin.tar.gz"],
-            // /jdks/openjdk/25/openjdk-25-ea+30/openjdk-25-ea+30_linux
+        } else if (jdk.getVendor().equals(VENDOR_OPENJDK) && "ea".equals(jdk.getDistributionVersion())) {
             repoUrl = "https://builds.es-jdk-archive.com/";
-
             // current pattern since 12.0.1
             artifactPattern = "jdks/openjdk/"
                 + jdk.getMajor()