Revert "Temporarily disable max inflight checks for mutating requests"

This reverts commit 4a28d1f800.

This commit was originally made to fix a bug that caused TokenCredentialRequest
to become slow when the server was idle for an extended period of time. This was
to address a Kubernetes issue that was fixed in 1.19.5 and onward. We are now
running with Kubernetes 1.20, so we should be able to pick up this fix.

internal/concierge/server/server.go

@@ -191,13 +191,6 @@ func getAggregatedAPIServerConfig(
 		return nil, err
 	}
 
-	// temporarily disable max inflight checks for mutating requests until we
-	// pick up a fix for https://github.com/kubernetes/kubernetes/issues/95300
-	// we do not need to set MaxRequestsInFlight to 0 because we are constantly
-	// hammered by the kubelet for /healthz and the api server for discovery
-	// which keeps the non-mutating request watermark histograms up to date
-	serverConfig.Config.MaxMutatingRequestsInFlight = 0
-
 	apiServerConfig := &apiserver.Config{
 		GenericConfig: serverConfig,
 		ExtraConfig: apiserver.ExtraConfig{