OpRoundtripTime telemetry is wrong (#15620)

## Description

In connections where have 2 or more OpRoundtripTime triggered within the
same connection, we will have incorrect values as we we do not reset
opProcessingTimes.
The second time and every time afterwards, durationNetwork is going to
be empty because it gets reset after the OpRoundtripTime is triggered
but opProcessingTimes.outboundPushEventTime does not get reset.

[Task
4006](https://dev.azure.com/fluidframework/internal/_workitems/edit/4006).

packages/runtime/container-runtime/src/connectionTelemetry.ts

@@ -285,6 +285,7 @@ class OpPerfTelemetry {
 			});
 			this.clientSequenceNumberForLatencyStatistics = undefined;
 			this.opPerfData = {};
+			this.opProcessingTimes = {};
 		}
 	}
 }