Clean up obsolete screen record code

- Remove launched flag WM_ENABLE_PARTIAL_SCREEN_SHARING_ENTERPRISE_POLICIES
- Delete layout and class files that were replaced:
screen_record_dialog -> screen_share_dialog
ScreenRecordDialogDelegate -> ScreenRecordPermissionDialogDelegate
- Remove unused variables
- Switch to mockito-kotlin

Flag: NONE removing old flag
Bug: 263964044
Test: atest modified test files
Change-Id: I1bf7d553ac31ff0b15fd82d62f6f714bb68f939e