[Launcher] Update conflict with locally compiled version

Release Type:
official vs. locally compiled

Version:
beta02-527 vs. locally compiled beta02

Platform(s):
windows

Describe the bug
exception dialog on update to latest beta

To Reproduce
Steps to reproduce the behavior:

1. compile xenko locally from master, set version to beta02
2. download lastest official beta via launcher

Expected behavior
launcher takes care of installing a specific version of the nuget packages, regardless of what is already in the nuget cache. to download the packages the nuget install command should probably use the -source nuget.org argument to ignore the local package sources.

Log and callstacks

An error occurred while installing version 3.1.0.1-beta02-0527.
Unable to find package Xenko.Core.MicroThreading with version (>= 3.1.0.1-beta02-0527)
•	Found 2 version(s) in Xenko Dev [ Nearest version: 3.1.0.1-beta02 ]
•	Found 0 version(s) in VL.Xenko Dev
•	Found 0 version(s) in VL Dev
•	Found 0 version(s) in Microsoft Visual Studio Offline Packages
•	Found 0 version(s) in vvvv Package source
•	Found 0 version(s) in nuget.org
•	Found 0 version(s) in Xenko
Could not restore package Xenko.GameStudio at Xenko.Core.Packages.NugetStore.<InstallPackage>d50.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Xenko.LauncherApp.ViewModels.PackageVersionViewModel.<>cDisplayClass550.<<Download>b_0>d.MoveNext()

Start with Xenko.LauncherApp.ViewModels.PackageVersionViewModel and the Xenko.Core.Packages.NugetStore installation path shown in the stack trace. Reproduce the update after compiling beta02 locally, then inspect how the launcher resolves package versions and sources. Done means the official beta installs successfully despite the locally cached package.