fix(exif): handle null byte padding after EXIF segment

[exoego]

Some JPEG files have null byte padding between segments that isn't accounted for in the segment length field.
This fix ensures the stream position is correctly advanced and skips any padding bytes.

Many JPEG decoders seem to handle this gracefully by scanning for the next 0xFF marker prefix.
This fix does the same - it's a robustness improvement for real-world malformed files.

This fixes foliojs/pdfkit#1175 and can be an advantage over jpeg-exif.

Note that I proposed jay-peg in foliojs/pdfkit#1678

[exoego]

Note) this image comes from foliojs/pdfkit#1175