Remove non-fonctional "JOB_NAME" custom value in build scans

It doesn't seem to work as we get "JOB null" on every build scan.
Even if it worked, it would most likely only display the top-level job,
e.g. `hibernate-orm-pipeline` on Jenkins, which doesn't give much
information.

gradle/gradle-enterprise.gradle

@@ -46,9 +46,6 @@ gradleEnterprise {
 
         uploadInBackground = !settings.ext.isCiEnvironment
 
-        if ( settings.ext.isCiEnvironment ) {
-            tag "JOB ${System.getenv('JOB_NAME')}"
-        }
         tag "JDK ${JavaVersion.current().toString()}"
         String db = rootProject.hasProperty( 'db' ) ? rootProject.properties.db : 'h2'
         tag db