[Synthetics UI] Prefer custom_heartbeat_id to monitor.id for Upti…

…me detail link when present (#143128)

* Prefer `custom_heartbeat_id` to `monitor.id` when present.

* Prefer `ConfigKey`.

x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_details/monitor_summary/last_ten_test_runs.tsx

@@ -118,6 +118,7 @@ export const LastTenTestRuns = () => {
     },
   ];
 
+  const historyIdParam = monitor?.[ConfigKey.CUSTOM_HEARTBEAT_ID] ?? monitor?.[ConfigKey.ID];
   return (
     <EuiPanel hasShadow={false} hasBorder css={{ minHeight: 200 }}>
       <EuiFlexGroup alignItems="center" gutterSize="s">
@@ -133,7 +134,8 @@ export const LastTenTestRuns = () => {
             iconType="list"
             iconSide="left"
             data-test-subj="monitorSummaryViewLastTestRun"
-            href={`${basePath}/app/uptime/monitor/${btoa(monitor?.id ?? '')}`}
+            disabled={!historyIdParam}
+            href={`${basePath}/app/uptime/monitor/${btoa(historyIdParam ?? '')}`}
           >
             {i18n.translate('xpack.synthetics.monitorDetails.summary.viewHistory', {
               defaultMessage: 'View History',