db_query_bound() expects 2nd param to be array

In sponsorship_delete_all(), passing the bug ID as an integer instead of
an array causes an error in ADOdb oci8 driver.
Database api: new db_update_blob() function

Issue #16336
Oracle: properly store file attachments as BLOBs

Uses new db_update_blob() function, instead of relying on hex-encoding
the binary data and passing the resulting string to db_query_bound()
because this method limits the size of attachments to 4000 bytes.

Fixes #16336