message: storage: trim `\0` at the tail of blob id
  With user specified blob id, there may be padding `\0` at the end,
  which must be trimmed when building blob file path from blob id.
diff: @@ -165,6 +165,7 @@ impl BlobInfo {
  chunk_count: u32,
  blob_features: BlobFeatures,
  ) -> Self {
  + let blob_id = blob_id.trim_end_matches('\0').to_string();
  let mut blob_info = BlobInfo {
  blob_index,
  blob_id,
  