Return SignedOut state after signin in UwpMsalProviderSample sample uwp application

## Describe the bug
A clear and concise description of what the bug is.

- [ ] Is this bug a regression in the toolkit? If so, what toolkit version did you last see it work:

## Steps to Reproduce
Steps to reproduce the behavior:
1. Download & Go to 'UwpMsalProviderSample' application and restore nuget packages
2. Change your client id and scopes in app.xaml.cs file
3. Run the application and click Sign In button
4. Sign in window will open & add your credentials [See image 1]
5. Check NewState property value, it will be "SignedOut" [See image 2]

## Expected behavior
It should allowed user to sign in successfully after adding credentials in sign in window.

## Screenshots

## Environment

```
NuGet Package(s):
CommunityToolkit.Authentication - v-7.1.1
CommunityToolkit.Authentication.Msal - v-7.1.1
CommunityToolkit.Graph - v-7.1.1
CommunityToolkit.Graph.Uwp - v-7.1.1
Microsoft.NETCore.UniversalWindowsPlatform - v-6.2.12
Package Version(s):
CommunityToolkit.Authentication - v-7.1.1
CommunityToolkit.Authentication.Msal - v-7.1.1
CommunityToolkit.Graph - v-7.1.1
CommunityToolkit.Graph.Uwp - v-7.1.1
Microsoft.NETCore.UniversalWindowsPlatform - v-6.2.12

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [Yes] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] Insider Build (xxxxx)

Device form factor:
- [Yes] Desktop
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio
- [ ] 2017 (version: )
- [ ] 2019 (version: )
- [ ] 2019 Preview (version: )
- [Yes] Community 2022 (17.1.5)