[RPP] fix entity mapper initialized to null bug

When trying to initialize the timelineDetailsView, entity mapper comes
back null. Initializing earlier before other work is done
seems to fix this

Bug:None
Change-Id: I125e3be92f2585d279797695ac9ed4bf439443a9
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6191071
Reviewed-by: Adam Raine <[email protected]>
Commit-Queue: Adriana Ixba <[email protected]>

Author: Adriana Ixba

front_end/panels/timeline/TimelineFlameChartView.ts

@@ -1101,6 +1101,7 @@ export class TimelineFlameChartView extends Common.ObjectWrapper.eventMixin<Even
     this.#selectedGroupName = null;
     this.#parsedTrace = newParsedTrace;
     this.#traceMetadata = traceMetadata;
+    this.#entityMapper = new Utils.EntityMapper.EntityMapper(this.#parsedTrace);
     Common.EventTarget.removeEventListeners(this.eventListeners);
     this.#selectedEvents = null;
     this.mainDataProvider.setModel(newParsedTrace, isCpuProfile);
@@ -1111,7 +1112,6 @@ export class TimelineFlameChartView extends Common.ObjectWrapper.eventMixin<Even
     this.refreshMainFlameChart();
     this.#updateFlameCharts();
     this.setMarkers(newParsedTrace);
-    this.#entityMapper = new Utils.EntityMapper.EntityMapper(this.#parsedTrace);
   }
 
   setInsights(