feat(new-trace): Allowing switching to indexed spans usage in old trace view. (#69067)

For testing only spans functionality in s4s.

Co-authored-by: Abdullah Khan <abdullahkhan@PG9Y57YDXQ.local>

Author: Abdkhan14

static/app/views/performance/traceDetails/index.tsx

@@ -97,6 +97,7 @@ class TraceSummary extends Component<Props> {
     const traceSlug = this.getTraceSlug();
     const {start, end, statsPeriod} = this.getDateSelection();
     const dateSelected = Boolean(statsPeriod || (start && end));
+    const backend = decodeScalar(location.query.backend);
 
     const content = ({
       isLoading,
@@ -147,7 +148,7 @@ class TraceSummary extends Component<Props> {
 
     return (
       <TraceFullDetailedQuery
-        type="detailed"
+        type={backend === 'indexedSpans' ? 'spans' : 'detailed'}
         location={location}
         orgSlug={organization.slug}
         traceId={traceSlug}