Pass operation type to BackupAgent

Pass @OperationType in BackupAgent#onCreate and use it to instantiate
BackupRestoreEventLogger.

Bug: 255376040
Test: Manual: 1. Log operationType to logcat in BackupAgent#onCreate
              2. adb shell bmgr backupnow android; verify
		 operationType=0 via logcat
	      3. adb shell bmgr restore 1 android; verify
		 operationType=1 via logcat
Change-Id: I4b2e337209f31aade91baa6900abced35591a0af