update ga to 2.18.0

Signed-off-by: Tao Liu <liutaoaz@amazon.com>

Author: Flyingliuhub

config/playground/helm/preview/helm-opensearch-dashboards.yaml

@@ -201,4 +201,4 @@ extraObjects: []
 # specify the external plugins to install
 plugins:
   enabled: true
-  installList: ["https://github.com/BionIT/google-analytics-plugin/releases/download/2.17.0/googleAnalytics-2.17.0.zip"]
+  installList: ["https://github.com/BionIT/google-analytics-plugin/releases/download/2.18.0/googleAnalytics-2.18.0.zip"]