container registries can't login to repo1.dso.mil even tho it supports Docker HTTP API V2

[aldass]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.79.0
• OS Version: Windows_NT x64 10.0.19044

Steps to Reproduce:

1. Add https://registry1.dso.mil as a Generic Docker Registry
2. Use valid UserID and PAT for https://registry1.dso.mil
3. In the Registries panel, click the registry1.dso.mil registry which gives the following:
   Error: Request to https://registry1.dso.mil/v2/_catalog?n=100 failed with status 401: Unauthorized

registry1.dso.mil is hosted by Project Harbor which is an an open source trusted cloud native registry project that stores, signs, and scans content.

The issue seems to be with vscode since doing a docker login -u {{USERID}} --password {{PAT}} registry1.dso.mil works just fine.

[bwateratmsft]

I will add this to the list in #869.