Fix DateTimeViewTest illegal access error

Even package path is the same, different classpath (bootclass vs test)
will be considered as different package that does not allow package access.
Also correct to verify twice detach.

Bug: 78506836
Test: atest FrameworksCoreTests:DateTimeViewTest
Change-Id: If60fe89049f5e4b8366c6e1e4d4e2d7e38a57b7c