XML fixtures can not be edited from GUI

[Griunvaldas]

https://github.com/holomekc/wiremock/blob/db52e068e7e3ea7b533f268700dcace794cc78e9/webapp/wiremock/src/app/services/util.service.ts#L267

JSON.parse gets XML instead of JSON and breaks. In UI, file contents appears to be empty, but in Network it can be seen that file contents is coming, but console has mentioned error.

If we copy XML contents, paste them to textarea and then save, it does actually save that XML.

Can this be fixed to return unformatted plain text instead in case response fixture is not JSON? It would really help our QA with mocking/testing SOAP webservices! :)