Make CancelFromNotificationUiTest more stable

CancelFromNotificationUiTest sometimes fails due to UiAutomator
opens floating options menu before file selection finished and
shows options menu for no item selection.

This CL fix to ensure to open options menu after the select file
operation finished.

Also made refactoring on CancelFromNotificationUiTest and
FileDeleteUiTest to use NotificationsBot for maintainability.

Bug: 80216781
Change-Id: Id8900b0be3168cbbf5281560733707c5a08238d0