Revert "Add experimental newest-first issue thread" (#5460)

This is actually bad. Glad it was under experiments.

ui/src/pages/IssueDetail.tsx

@@ -592,7 +592,6 @@ type IssueDetailChatTabProps = {
   issueId: string;
   companyId: string;
   projectId: string | null;
-  newestFirstIssueThreadEnabled: boolean;
   issueStatus: Issue["status"];
   issueWorkMode: IssueWorkMode;
   executionRunId: string | null;
@@ -656,7 +655,6 @@ const IssueDetailChatTab = memo(function IssueDetailChatTab({
   issueId,
   companyId,
   projectId,
-  newestFirstIssueThreadEnabled,
   issueWorkMode,
   issueStatus,
   executionRunId,
@@ -857,7 +855,6 @@ const IssueDetailChatTab = memo(function IssueDetailChatTab({
       ) : null}
       <IssueChatThread
         composerRef={composerRef}
-        newestFirst={newestFirstIssueThreadEnabled}
         comments={commentsWithRunMeta}
         interactions={interactions}
         feedbackVotes={feedbackVotes}
@@ -1318,12 +1315,6 @@ export function IssueDetail() {
   });
   const resolvedHasActiveRun = issue ? shouldTrackIssueActiveRun(issue) && hasActiveRun : hasActiveRun;
   const hasLiveRuns = liveRunCount > 0 || resolvedHasActiveRun;
-  const { data: experimentalSettings } = useQuery({
-    queryKey: queryKeys.instance.experimentalSettings,
-    queryFn: () => instanceSettingsApi.getExperimental(),
-    placeholderData: keepPreviousDataForSameQueryTail(issueId ?? "pending"),
-  });
-  const newestFirstIssueThreadEnabled = experimentalSettings?.enableNewestFirstIssueThread === true;
   useEffect(() => {
     if (!hasLiveRuns && locallyQueuedCommentRunIds.size > 0) {
       setLocallyQueuedCommentRunIds(new Map());
@@ -3790,7 +3781,6 @@ export function IssueDetail() {
               issueId={issue.id}
               companyId={issue.companyId}
               projectId={issue.projectId ?? null}
-              newestFirstIssueThreadEnabled={newestFirstIssueThreadEnabled}
               issueStatus={issue.status}
               issueWorkMode={issue.workMode ?? "standard"}
               executionRunId={issue.executionRunId ?? null}