Support bundle download endpoints could distinguish success and failure status codes in OpenAPI

[ahl]

this is probably wrong; we might return a 200 or 206.

[smklein]

I think this is the right approach for all support bundle endpoints - I either forgot or never knew about FreeformBody, but it seems vastly superior to just returning a raw Body to be vaguely interpreted.

I'll give a shot at updating all these response endpoints in #7187 to confirm this works with the integration tests

[smklein]

Following up on comments made in chat:

• I think this is the right-ish direction (would like to make possible return values explicit)
• However, FreefromBody appears to drop all the response headers
• This is a problem for range requests, which would like to return headers
• We might need to patch dropshot to make this work

[ahl]

Yeah. I don't think we can do this right now, but ideally we'd like the following to appear in the OpenAPI document:

• range-related headers (both for requests and responses)
• error response codes
• multiple success responses (200 and 206)
• content type for the output ("application/octet-stream" I think?)