server/grpc_service: new AskSplitRequest could be removed

[AndreMouche]

Enhancement Task

It seems we do not need to create a new AskSplit in the function AskSplitRegion, use request directly instead.

pd/server/grpc_service.go

Lines 1066 to 1072 in 9f10a51

	if request.GetRegion() == nil {
	return nil, errors.New("missing region for split")
	}
	req := &pdpb.AskSplitRequest{
	Region: request.Region,
	}
	split, err := rc.HandleAskSplit(req)

[AndreMouche]

Meanwhile, similar logic in AskBatchSplit

pd/server/grpc_service.go

Lines 1111 to 1115 in 9f10a51

	req := &pdpb.AskBatchSplitRequest{
	Region: request.Region,
	SplitCount: request.SplitCount,
	}
	split, err := rc.HandleAskBatchSplit(req)