Update introspect mock/unit test to account for admin secret name change.

Author: Tom Barnes

src/integration-tests/introspector/wl-job.yamlt

@@ -31,7 +31,7 @@ spec:
           value: "${NODEMGR_HOME}"
         - name: LOG_HOME
           value: "${LOG_HOME}"
-        - name: ADMIN_SECRET_NAME
+        - name: CREDENTIALS_SECRET_NAME
           value: "${WEBLOGIC_CREDENTIALS_SECRET_NAME}"
         image: "${WEBLOGIC_IMAGE_NAME}:${WEBLOGIC_IMAGE_TAG}"
         imagePullPolicy: ${WEBLOGIC_IMAGE_PULL_POLICY}