No body in POST requests when digest auth is enabled

**Describe the bug**
Reproduced with XML body.
When digest auth is enabled, request contains only URL, but no body. So server just drop connection, no reply with 401 and WWW-Authenticate.

**To Reproduce**
Steps to reproduce the behavior:
1. Create new POST request
2. Select XML body type
3. Paste any XML into XML-field
4. Select Digest Auth and set USERNAME and PASSWORD fields
2. Click on 'Send'
4. See error

Wireshark window screenshot demonstrate this issue results.
Pay attention to the Content-Length : 0, and Content-Type : application/xml

**Expected behavior**
1. Send full request (with body)
2. Get 401 Unauthorized reply from server with WWW-Authenticate
3. Send full request again with Authorization
4. Get reply

**Screenshots**


**Desktop (please complete the following information):**
- OS: Ubuntu 18.04.4 LTS
- Installation Method: homebrew
- App Version v7.1.1

Start by reproducing the XML POST with Digest Auth in Insomnia v7.1.1 and capture the request in Wireshark, as shown in the issue screenshots. Trace the request and authentication flow until the body is lost; done means the initial request reaches the server with its body, the 401 response is received, and the authenticated retry also includes the body.

Written by the indexing model from the issue text.