[APM] Review feedback from distribution + transaction metrics (#78752)

Author: dgieselaar

x-pack/plugins/apm/public/hooks/useTransactionDistribution.ts

@@ -69,13 +69,11 @@ export function useTransactionDistribution(urlParams: IUrlParams) {
           // selected sample was not found. select a new one:
           // sorted by total number of requests, but only pick
           // from buckets that have samples
-          const bucketsSortedByPreference = response.buckets
+          const bucketsSortedByCount = response.buckets
             .filter((bucket) => !isEmpty(bucket.samples))
             .sort((bucket) => bucket.count);
 
-          const preferredSample = maybe(
-            bucketsSortedByPreference[0]?.samples[0]
-          );
+          const preferredSample = maybe(bucketsSortedByCount[0]?.samples[0]);
 
           history.push({
             ...history.location,

x-pack/test/apm_api_integration/basic/tests/transaction_groups/distribution.ts

@@ -17,14 +17,10 @@ export default function ApiTest({ getService }: FtrProviderContext) {
   const archiveName = 'apm_8.0.0';
   const metadata = archives_metadata[archiveName];
 
-  // url parameters
-  const { start, end } = metadata;
-  const uiFilters = {};
-
   const url = `/api/apm/services/opbeans-java/transaction_groups/distribution?${qs.stringify({
-    start,
-    end,
-    uiFilters,
+    start: metadata.start,
+    end: metadata.end,
+    uiFilters: {},
     transactionName: 'APIRestController#stats',
     transactionType: 'request',
   })}`;