Don't use ramdisk for encryption at rest testing

.ci/jobs.t/elastic+elasticsearch+periodic+ear.yml

@@ -1,7 +1,6 @@
 ---
 - job:
     name: elastic+elasticsearch+%BRANCH%+periodic+ear
-    workspace: /dev/shm/elastic+elasticsearch+%BRANCH%+periodic+ear
     display-name: "elastic / elasticsearch # %BRANCH% - encryption at rest"
     description: "The Elasticsearch %BRANCH% branch encryption at rest compatibility tests.\n\n"
     node: packaging-large