Describe the bug

A clear and concise description of what the bug is.

When pressing arrow keys while focusing a RadialGauge and narrator is turned on, the sample app crashes.

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

Steps to Reproduce

• Can this be reproduced in the Sample App? (Either in a sample as-is or with new XAML pasted in the editor.) If so, please provide custom XAML or steps to reproduce. If not, let us know why it can't be reproduced (e.g. more complex setup, environment, dependencies, etc...)

Steps to reproduce the behavior:

1. Start narrator (Ctrl+WinKey+Enter)
2. Focus RadialGauge
3. Hit arrow key (e.g. left-arrow)

Expected behavior

A clear and concise description of what you expected to happen.
App should not just close itsself

Screenshots

If applicable, add screenshots to help explain your problem.

Environment

NuGet Package(s): 

Package Version(s): 

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] May 2020 Update (19041)
- [x] Insider Build (build number: 20236)

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] May 2020 Update (19041)
- [ ] Insider Build (xxxxx)

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

Visual Studio 
- [ ] 2017 (version: )
- [ ] 2019 (version: ) 
- [ ] 2019 Preview (version: )

Additional context

Without narrator, keyboard navigation works just fine.
Also the announced description of the RadialGauge is a bit confusing: "RadialGague, Unit units, custom", in addition to that the current value doesn't seem to get announced.