Cosmetic changes on Scoped Directory Access classes:

- Renamed OpenExternalDirectoryActivity to ScopedAccessActivity
- Removed unused code

Test: atest CtsAppSecurityHostTestCases:ScopedDirectoryAccessTest
Bug: 63720392

Change-Id: If73c66a804c4d2585e5f5d5c6620307004e04a23
6 files changed