message: nydus-image: make blob uncompressed size align to 4096
  Now that we've put a sanity check in RafsV6Blob's validate(), this
  makes blob's uncompressed size align to 4096 which is EROFS_BLOCK_SIZE
  in use.
diff: @@ -367,7 +367,8 @@ impl Node {
  let pre_compress_offset = blob_ctx.compress_offset;
  blob_ctx.compress_offset += compressed_size as u64;
  - blob_ctx.decompressed_blob_size = blob_ctx.decompress_offset + chunk_size as u64;
  + blob_ctx.decompressed_blob_size =
  + blob_ctx.decompress_offset + aligned_chunk_size as u64;
  blob_ctx.compressed_blob_size += compressed_size as u64;
  blob_ctx.decompress_offset += aligned_chunk_size as u64;
  blob_ctx.blob_hash.update(&compressed);
  