Ensure that when AcceptMessageSession times out, it doesnt report it …

…as Exception in AppInsights (DiagnosticSource) (#6919)

fixes issue #6813

sdk/servicebus/Microsoft.Azure.ServiceBus/src/SessionClient.cs

@@ -320,7 +320,7 @@ public async Task<IMessageSession> AcceptMessageSessionAsync(string sessionId, T
             }
             catch (Exception exception)
             {
-                if (isDiagnosticSourceEnabled)
+                if (isDiagnosticSourceEnabled && !(exception is ServiceBusTimeoutException))
                 {
                     this.diagnosticSource.ReportException(exception);
                 }