Manifest .json file hosted on NAS isn't parsed correctly.

Similar to referenced issue. Vagrant hosted on a nas to be able to share with collaborators. I can't modify the content type of the file sent, though referenced issue suggested it didn't fix it either. Vagrant fails to parse json file when loaded over https and gves error:
`bsdtar: Error opening archive: Unrecognised archive format.`
### Vagrant version
Vagrant 2.2.7
### Host operating system
PopOS 19.10
### Debug output
Loaded .json over https, content type not correct.
https://gist.github.com/Logiar/a0b8aba9377dc60570916a8a2c845196

Loaded same file over mounted samba share and parsed correctly.
https://gist.github.com/Logiar/44ee3c72de17b7f472bfd26805706046
Host replaced, can provide public address of the json in private message if necessary.

### Expected behavior
Vagrant recognises that the file is a manifest file by extension/content even if content type sent is incorrect. Alternatively some option to instruct vagrant to read it as a manifest would work too.

### Actual behavior
Vagrant fails to read manifest file.

### Steps to reproduce

1. Host a manifest file on a NAS, which sends wrong content type?
2. Try to use manifest file to import box.
3. Observe crash.

### References
- GH-5336

Start by reviewing referenced issue GH-5336 and the supplied debug output, then reproduce importing a manifest hosted over HTTPS with an incorrect Content-Type and compare it with the Samba case. Done means Vagrant imports the same manifest over HTTPS despite the NAS response, with the behavior covered by a regression test.

Written by the indexing model from the issue text.