[APM] Don't use transaction metrics if set to never (#117370) (#117415)

Closes #117226.

Co-authored-by: Dario Gieselaar <[email protected]>

x-pack/plugins/apm/server/lib/helpers/aggregated_transactions/index.ts

@@ -63,18 +63,23 @@ export async function getSearchAggregatedTransactions({
   apmEventClient: APMEventClient;
   kuery: string;
 }): Promise<boolean> {
-  const searchAggregatedTransactions = config.searchAggregatedTransactions;
+  switch (config.searchAggregatedTransactions) {
+    case SearchAggregatedTransactionSetting.always:
+      return kuery
+        ? getHasAggregatedTransactions({ start, end, apmEventClient, kuery })
+        : true;
 
-  if (
-    kuery ||
-    searchAggregatedTransactions === SearchAggregatedTransactionSetting.auto
-  ) {
-    return getHasAggregatedTransactions({ start, end, apmEventClient, kuery });
-  }
+    case SearchAggregatedTransactionSetting.auto:
+      return getHasAggregatedTransactions({
+        start,
+        end,
+        apmEventClient,
+        kuery,
+      });
 
-  return (
-    searchAggregatedTransactions === SearchAggregatedTransactionSetting.always
-  );
+    case SearchAggregatedTransactionSetting.never:
+      return false;
+  }
 }
 
 export function getTransactionDurationFieldForAggregatedTransactions(