add galaxy event for the cloud callout on the install page

Author: Blargian

docs/getting-started/install/install.mdx

@@ -26,7 +26,7 @@ import {CardPrimary} from '@clickhouse/click-ui/bundled';
     infoText="Get started free"
     infoUrl="https://auth.clickhouse.cloud/"
     isSelected
-    onButtonClick={function Da(){}}
+    onButtonClick={galaxyOnClick('docs.installCloudCallout.buttonClicked')}
     size="md"
     title="ClickHouse Cloud"
     topBadgeText="Recommended"