Fix CustomData import in DataEngine (#2207)

Author: faysou

nautilus_trader/data/engine.pyx

@@ -48,7 +48,6 @@ from nautilus_trader.common.component cimport RES
 from nautilus_trader.common.component cimport Clock
 from nautilus_trader.common.component cimport Component
 from nautilus_trader.common.component cimport MessageBus
-from nautilus_trader.common.component cimport TestClock
 from nautilus_trader.core.correctness cimport Condition
 from nautilus_trader.core.data cimport Data
 from nautilus_trader.core.datetime cimport dt_to_unix_nanos
@@ -76,6 +75,7 @@ from nautilus_trader.model.book cimport OrderBook
 from nautilus_trader.model.data cimport Bar
 from nautilus_trader.model.data cimport BarAggregation
 from nautilus_trader.model.data cimport BarType
+from nautilus_trader.model.data cimport CustomData
 from nautilus_trader.model.data cimport DataType
 from nautilus_trader.model.data cimport InstrumentClose
 from nautilus_trader.model.data cimport InstrumentStatus