Part of [[ https://linear.app/comm/issue/ENG-3975/rename-holder-blobhash-in-function-and-variable-names-where-applicable | ENG-3975 ]].
The same as D8323, but for web - Now the `holder` isn't accurate, I decided to name this value `blobURI` because it is of format: either `https://keyserver/uploads/...` or `blob-service://blob-hash`
Depends on D8322