Change engine pack size message back to debug

I think this is a good standard to follow for the rest of the size-related messages. They should have bounds checking which raises an exception if it fails, and debug logs which print out the size in case you need to know how much space is left.

coilsnake/model/eb/musicpack.py

@@ -897,7 +897,7 @@ def save_to_parts(self) -> None:
             raise InvalidUserDataError("Data for engine pack ${:02X} is too long by {} bytes. "
                                        "Maybe your \"in-engine\" songs are too large.".format(self.pack_num, overage))
         # Have a helpful debug output for the user
-        log.info("Engine pack has %d bytes of free space available.", DYNAMIC_SONG_DATA_START - song_output_ptr)
+        log.debug("Engine pack has %d bytes of free space available.", DYNAMIC_SONG_DATA_START - song_output_ptr)
         output_parts += always_loaded_song_parts
 
         # Get dynamically loaded song data that is in this pack (Gas Station 1 in vanilla)