FifoDataFile: Improve error handling when reading

[Pokechu22]

The main thing I'm targeting here is opening a 0-byte file, as currently that produces the nonsensical error message "The DFF's minimum loader version (1) exceeds the version of this FIFO Player (5)" (due to the check on header.fileId != FILE_ID). I often end up opening a 0-byte file if I try to open it while it's still downloading (as firefox creates a 0-byte file as well as a .tmp file).

The other checks were added for completeness; note that Common::IOFile uses RAII so the manual close calls aren't needed. I removed them for Load but haven't touched anything in Save.

[dolphin-emu-bot]

FifoCI detected that this change impacts graphical rendering. Here are the behavior differences detected by the system:

• ss-timestone on ogl-lin-mesa: failed to render
• ss-timestone on sw-lin-mesa: failed to render
• ss-timestone on ogl-lin-radeon: failed to render
• ss-timestone on uberogl-lin-radeon: failed to render

_{^{automated-fifoci-reporter}}

[Pokechu22]

ss-timestone appears to be corrupt (it has a bad offset for memory updates on the 2nd frame, and the 2nd and 3rd frames in general seem messed up), and has since been disabled on fifo.ci.