remove useless import in ObserverService

import java.io.File;

import java.io.FileFilter;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.HashMap;

import java.util.List;

import java.util.ListIterator;

import java.util.Map;

import java.util.stream.Stream;

import foundation.e.drive.database.DbHelper;

import foundation.e.drive.fileFilters.CrashlogsFileFilter;