fix(builder/monitor): Fix # of runs count on first load (#7558)

Return mutated copy rather than in-place mutated `flowRuns` in `refreshFlowRuns(..)`

Fixes #7507

rnd/autogpt_builder/src/app/monitor/page.tsx

@@ -82,7 +82,7 @@ const Monitor = () => {
         else {
           flowRuns.push(flowRun)
         }
-        return flowRuns
+        return [...flowRuns]
       }));
     }));
   }