Include cross account bucket permissions for downloader Lambda role.

[sharkinsspatial]

No description provided.

[ceholden]

Hey @sharkinsspatial, I think this ticket was completed as part of this commit that added write permissions to the downloader Lambda function to the "upload bucket",
e202d60#diff-5e055f6f79c9ff7c0c507afba31ffe5feb79c67eb89a43646f0a503d619c1169R346-R351

Does that sound right? I didn't see this when I was working on getting us fully on IAC but I think we're all set now. If not I'd be happy to take this to wrap up any permissions/IAC related concerns