Fix Run Timeline splitting out ad hoc jobs (#22520)

## Summary & Motivation


https://dagsterlabs.slack.com/archives/C070G3UNNLW/p1718238323769339?thread_ts=1718238288.884269&cid=C070G3UNNLW


before: multiple rows for adhoc materializations
<img width="1332" alt="Screenshot 2024-06-12 at 8 36 48 PM"
src="https://github.com/dagster-io/dagster/assets/2286579/b0310a78-465c-42ab-9231-e83cad77ee55">


after: just a single one:
<img width="1579" alt="Screenshot 2024-06-12 at 8 37 01 PM"
src="https://github.com/dagster-io/dagster/assets/2286579/51f4dd24-9005-4958-bdf2-57f633731e29">

js_modules/dagster-ui/packages/ui-core/src/runs/useRunsForTimeline.tsx

@@ -406,6 +406,7 @@ export const useRunsForTimeline = ({
     if (!workspaceOrError || workspaceOrError.__typename === 'PythonError' || _end < Date.now()) {
       return jobsWithCompletedRunsAndOngoingRunsValues;
     }
+    const addedAdHocJobs = new Set();
     const jobs: TimelineJob[] = [];
     for (const locationEntry of workspaceOrError.locationEntries) {
       if (
@@ -450,6 +451,13 @@ export const useRunsForTimeline = ({
           const isAdHoc = isHiddenAssetGroupJob(pipeline.name);
           const jobKey = makeJobKey(repoAddress, pipeline.name);
 
+          if (isAdHoc) {
+            if (addedAdHocJobs.has(jobKey)) {
+              continue;
+            }
+            addedAdHocJobs.add(jobKey);
+          }
+
           const jobName = isAdHoc ? 'Ad hoc materializations' : pipeline.name;
 
           const jobRuns = Object.values(runsByJobKey[jobKey] || {});
@@ -553,7 +561,9 @@ export const useRunsForTimeline = ({
 };
 
 export const makeJobKey = (repoAddress: RepoAddress, jobName: string) =>
-  `${jobName}-${repoAddressAsHumanString(repoAddress)}`;
+  `${isHiddenAssetGroupJob(jobName) ? '__adhoc__' : jobName}-${repoAddressAsHumanString(
+    repoAddress,
+  )}`;
 
 const RUN_TIMELINE_FRAGMENT = gql`
   fragment RunTimelineFragment on Run {