Switch reference time to ZonedDateTime

Bug: 74838195
Test: atest FrameworksCoreTests:TextClassificationManagerTest
Test: atest FrameworksCoreTests:TextClassificationTest
Test: atest CtsViewTestCases:TextClassificationManagerTest
Test: atest CtsViewTestCases:TextClassifierValueObjectsTest
Change-Id: I0df9dddf415fa558435553336a8a0a15621e9b05
4 files changed