Remove onboarding container jdk15 and buildpack tests (#7859) (#7872)

* Onboarding tests: remove weblog container-jdk15
* Remove buildpack weblog

Co-authored-by: Roberto Montero <[email protected]>

Author: yiliangzhou

.gitlab-ci.yml

@@ -216,10 +216,8 @@ package-oci:
 onboarding_tests_installer:
   parallel:
     matrix:
-      - ONBOARDING_FILTER_WEBLOG: [test-app-java, test-app-java-container, test-app-java-container-jdk15, test-app-java-alpine]
+      - ONBOARDING_FILTER_WEBLOG: [test-app-java, test-app-java-container, test-app-java-alpine]
         SCENARIO: [ SIMPLE_INSTALLER_AUTO_INJECTION, SIMPLE_AUTO_INJECTION_PROFILING ]
-      - ONBOARDING_FILTER_WEBLOG: [test-app-java-buildpack]
-        SCENARIO: [ SIMPLE_INSTALLER_AUTO_INJECTION ]
 
 onboarding_tests_k8s_injection:
   variables: