Revert "[8.19][Automation] Update versions (#9447)" (#9476)

This reverts commit 6372b67.

Author: ycombinator

dev-tools/packaging/templates/linux/preinstall.sh.tmpl

@@ -10,13 +10,6 @@ if systemctl list-unit-files --type=service | grep -q "^${SERVICE_NAME}.service"
 
     # Remove the vault directory if it exists
     if [ -d "/opt/Elastic/Endpoint/state/vault" ]; then
-        # we need to stop the agent to prevent it from invoking endpoint
-        if systemctl --quiet is-active elastic-agent; then
-          echo "elastic-agent is running, stopping it"
-          systemctl --quiet stop elastic-agent
-        else
-          echo "elastic-agent is not running"
-        fi
 
         # Check if the endpoint is running
         if systemctl --quiet is-active $SERVICE_NAME; then

testing/integration/testdata/.upgrade-test-agent-versions.yml

@@ -5,7 +5,7 @@
 # upgrade integration tests.
 
 testVersions:
-  - 8.18.5
-  - 8.17.10
+  - 8.18.4
+  - 8.17.9
   - 7.17.30-SNAPSHOT
   - 7.17.29