Log Message:
kimageformats: update to 5.61.0

5.60.0
  QImage::byteCount -> QImage::sizeInByes
5.58.0
  tga: don't try to read more than max_palette_size into palette
  tga: memset dst if read fails
  tga: memset the whole palette array, not only the palette_size
  Initialize the unread bits of _starttab
  xcf: Fix uninitialized memory use on broken documents
  ras: Don't overread input on malformed files
  xcf: layer is const in copy and merge, mark it as such