Mobile client file uploads are missing the `Content-Type` header in the MultipartFormDataContent.

[BlackDex]

Steps To Reproduce

This isn't an actual issue with the Bitwarden servers, but more with the Vaultwarden servers. That said though, I think the issue I'm going to describe should be fixed, since this will be more RFC complaint, and it will bring the mobile clients to match all other clients which do work correctly.

During a file upload which happens here: https://github.com/bitwarden/mobile/blob/f0ebc5e644453f9d2fa47de002451c5afe713a13/src/Core/Services/BitwardenFileUploadService.cs#L19

It creates a new MultipartFormDataContent but it does not add Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/octet-stream") to tell the receiving server that the data is an octet-stream. All the other clients seem to correctly send this header within the Multipart Boundary, but the Mobile client does not.

cli:

----------------------------912273455857274694771742
Content-Disposition: form-data; name="data"; filename="2.Fs5equeDmj6fyIUaXUcshg==|GrI8mEOTFZvQ2jLUUhMdHVRN2lLXCaWwVNMLSqsf1mw=|Zvz3r6rf/bxzQI1menhmWxbWoOSB9muLXPcTgsvt9zY="
Content-Type: application/octet-stream

...binary-data...

mobile:

----BWMobileFormBoundary637944497908437220
Content-Disposition: form-data; name=data; filename="2.G1wXKOe1mvSACgYFeXT/LQ==|DbAd+b/BsuRQHekNw0eloE4cTsfBNGBPJrRLPYKaSRE=|AqrrCG0fWdZqLuG9uUFzGYNfES2HzqugRdNE7BKRdFw="; filename*=utf-8''2.G1wXKOe1mvSACgYFeXT%2FLQ%3D%3D|DbAd+b%2FBsuRQHekNw0eloE4cTsfBNGBPJrRLPYKaSRE%3D|AqrrCG0fWdZqLuG9uUFzGYNfES2HzqugRdNE7BKRdFw%3D

...binary-data...

Expected Result

mobile:

----BWMobileFormBoundary637944497908437220
Content-Disposition: form-data; name=data; filename="2.G1wXKOe1mvSACgYFeXT/LQ==|DbAd+b/BsuRQHekNw0eloE4cTsfBNGBPJrRLPYKaSRE=|AqrrCG0fWdZqLuG9uUFzGYNfES2HzqugRdNE7BKRdFw="; filename*=utf-8''2.G1wXKOe1mvSACgYFeXT%2FLQ%3D%3D|DbAd+b%2FBsuRQHekNw0eloE4cTsfBNGBPJrRLPYKaSRE%3D|AqrrCG0fWdZqLuG9uUFzGYNfES2HzqugRdNE7BKRdFw%3D
Content-Type: application/octet-stream

...binary-data...

Actual Result

mobile:

----BWMobileFormBoundary637944497908437220
Content-Disposition: form-data; name=data; filename="2.G1wXKOe1mvSACgYFeXT/LQ==|DbAd+b/BsuRQHekNw0eloE4cTsfBNGBPJrRLPYKaSRE=|AqrrCG0fWdZqLuG9uUFzGYNfES2HzqugRdNE7BKRdFw="; filename*=utf-8''2.G1wXKOe1mvSACgYFeXT%2FLQ%3D%3D|DbAd+b%2FBsuRQHekNw0eloE4cTsfBNGBPJrRLPYKaSRE%3D|AqrrCG0fWdZqLuG9uUFzGYNfES2HzqugRdNE7BKRdFw%3D

...binary-data...

Screenshots or Videos

No response

Additional Context

If i were able to create a PR i would, but all the stuff needed to build/compile/test and the knowledge on this language is a bit to much ;). And I would rather leave it to the experts here. I think this is a very small change for someone who has the knowledge.

Operating System

Android, iOS

Operating System Version

No response

Device

No response

Build Version

Version: 2022.6.2 (4851)

Beta

• [ ] Using a pre-release version of the application.