Ported TextClassificationManagerPerfTest from Settings to DeviceConfig.

We dropped legacy Settings after ag/9852595, we should change to use
DeviceConfig here. No performance issue observed after appling change.

Bug: 148831327
Test: frameworks/base/apct-tests/perftests/textclassifier/run.sh
and make sure the config is set to default after test.

Change-Id: I2c95d12561373f8711fc548a4a9050a0bc5a0377