chore(server): optional originalMimeType in asset response payload

[alextran1502]

No description provided.

[jrasm91]

You still need to disable loading the original image if the shared link doesn't allow downloads.

[jrasm91]

Ideally we should add some e2e tests to verify this "load original" logic, as this same issue seems to get reintroduced every few months. Specifically:

• gif is a format that the original should load for
• shared links should load the original gif.
• shared links with downloads turned off should not load the original.

[jrasm91]

Noice, ty.