To get that apk back you can extract it from the ftf, I wouldn't worry about it though.
Guide to get the apk back;
1) Open the ftf with WinRAR (which can be downloaded from
here) and extract the system.sin file to your desktop.
2) Open flashtool (downloaded from
here) and select Tools > Sin Editor > Three dots button. Open the system.sin file with flashtool and then Extract data, this makes a system.ext4.
3) Once that is done download Ext2Explore from
here and open it
as an administrator (this is important).
4) In Ext2Explore click File > Open Image and then select your system.ext4. Double click the file it opens and then double click app. Then find VoicedDialer.apk and VoiceDialer.odex and once you find them right click on them and click save. Save them both to your desktop.
5) Go grab something to drink for managing to extract the files successfully.
