Fix ExifInterface for .heic when meta is at the end

available() bytes is counted after the last read position,
after the seek to new position, size should be compared
with the avaliable directly (without adding position).

bug: 120086693
test: Open .heic files in Downloads/Photos that's either
very small (b/117625929, b/111897855), or with the meta
at the very end (b/120086693). There shouldn't be error
in ExifInterface.
Change-Id: I37ac57823b26f03bb0ba555ee6213cf999942d21