Fix visualization for recordings in other languages.

[Daniele-Tentoni]

Now, if user record a call in a language, the file saved in file system has a name in that language. Changing the language, the recording is not shown because formatter can't understand the file name.

With this fix, the file name is in en_US locale in any case and is read in that locale in any case, so every recording is shown in the list view.

This problem is resolved in our fork of the project with those lines of code. There's no issues in list view headers views and the reproduction of the audio files has no issues.