Removed github package source from the workflow

Author: FrostyApeOne

.github/workflows/dotnet-ci.yml

@@ -42,9 +42,6 @@ jobs:
     - name: Install dotnet reportgenerator
       run: dotnet tool install --global dotnet-reportgenerator-globaltool
 
-    - name: Add nuget package source
-      run: dotnet nuget add source --username USERNAME --password ${{ secrets.GITHUB_TOKEN }} --store-password-in-clear-text --name github "https://nuget.pkg.github.com/DFE-Digital/index.json"
-
     - name: Restore dependencies
       run: dotnet restore DfE.ExternalApplications.Web.sln