Merged PR 313063: Onboard to CFS by updating feed configuration

Fix the following to be compliant to Central Feed Services (CFS):
1. Add missing feed configuration in PowerBI.API & PowerBI.API.Tests projects.
2. Update .nuget/NuGet.Config to use Azure Artifacts feed.

Also, remove config from nuget restore to pass the auth as mentioned in this [doc](https://onebranch.visualstudio.com/OneBranch/_wiki/wikis/OneBranch.wiki/4787/Consuming-Packages-in-a-CDPx-Pipeline?anchor=nuget)

.pipelines/pipeline.user.windows.yml

@@ -11,6 +11,14 @@ signing_options:
   codesign_validation_glob_pattern: 'regex|.+(?:exe|dll)$;-|*.nd.dll;-|.gdn\**'
   codesign_validation_break_build: true
 
+package_sources:
+  nuget:
+    config_files:
+      - include:
+        - "./sdk/.nuget/NuGet.Config"
+        - "./sdk/PowerBI.Api/NuGet.Config"
+        - "./sdk/PowerBI.Api.Tests/NuGet.Config" 
+
 restore:
   commands:
     - !!defaultcommand

scripts/nuget-restore.cmd

@@ -16,7 +16,7 @@ call .\init-dev-cmd.cmd
 echo =====================================================
 echo "Restoring Nuget packages for PowerBI.CSharp.Sdk.sln"
 echo =====================================================
-nuget restore -NonInteractive "%~dp0..\sdk\PowerBI.CSharp.Sdk.sln" -ConfigFile "%~dp0..\sdk\.nuget\NuGet.Config"
+nuget restore -NonInteractive "%~dp0..\sdk\PowerBI.CSharp.Sdk.sln"
 
 set EX=%ERRORLEVEL%
 if "%EX%" neq "0" (

sdk/.nuget/NuGet.Config

@@ -2,6 +2,6 @@
 <configuration>
   <packageSources>
     <clear />
-    <add key="NuGet official package source" value="https://nuget.org/api/v2/" />
+    <add key="PublicPackages" value="https://pkgs.dev.azure.com/powerbi/embedded/_packaging/embedded_PublicPackages/nuget/v2" />
   </packageSources>
 </configuration>

sdk/PowerBI.Api.Tests/NuGet.config

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="PublicPackages" value="https://pkgs.dev.azure.com/powerbi/embedded/_packaging/embedded_PublicPackages/nuget/v2" />
+  </packageSources>
+</configuration>

sdk/PowerBI.Api/NuGet.config

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="PublicPackages" value="https://pkgs.dev.azure.com/powerbi/embedded/_packaging/embedded_PublicPackages/nuget/v2" />
+  </packageSources>
+</configuration>