MediaConverter does not handle errors gracefully when sniffing files (easy)

[yourpalal]

MediaFileInfo::LoadInfo() ignores many return codes and can end up with a GIGO situation. Some examples are:

*should check track->InitCheck() after getting the track from TrackAt()

(MediaFileInfo.cpp:37)

*should check return of track->EncodedFormat()

(MediaFileInfo.cpp:39)

*should check return of track->DecodedFormat()

(MediaFileInfo.cpp:43)

*should check return of track->GetCodecInfo()

(MediaFileInfo.cpp:46)

There are similar problems when sniffing audio tracks (MediaFileInfo.cpp:58-88)

Once those are fixed, LoadInfo() should also return a status_t, which should be checked in MediaFileInfoView::Update().