Some custom repositories are failing to sync with error "This field may not be blank" after upgrading to Red Hat Satellite 6.11

Issue

• After upgrading to Red Hat Satellite 6.11, some of the custom repositories are failing to get synchronized with the following error.

  Exception:
  PulpRpmClient::ApiError: Error message: the server returns an error
  HTTP status code: 400
  Response headers: {"Date"=>"Wed, 09 Nov 2022 15:07:29 GMT", "Server"=>"gunicorn", "Content-Type"=>"application/json", "Vary"=>"Accept,Cookie", "Allow"=>"GET, PUT, PATCH, DELETE, HEAD, OPTIONS", "X-Frame-Options"=>"DENY", "Content-Length"=>"89", "X-Content-Type-Options"=>"nosniff", "Referrer-Policy"=>"same-origin", "Correlation-ID"=>"ac17a33d-bea6-44e8-85b0-fd166cbd806d", "Access-Control-Expose-Headers"=>"Correlation-ID", "Via"=>"1.1 satellite.example.com", "Connection"=>"close"}
  Response body: {"username":["This field may not be blank."],"password":["This field may not be blank."]}
  

• Inspecting the repository from Satellite UI --> Content --> Products page, does not shows any username or password mentioned in the Upstream Authorization field as well.