Rainway web client shows modal, empty alert that cannot be dismissed

[riverar]

Rainway app version 1.0.15.0 Windows 10 1903 18362.263

Repro steps:

1. Open Rainway for Web app
2. Start streaming the desktop (or a title)
3. Stop capturing the mouse cursor and click the X button on the window
4. When asked to leave the app, click Cancel
5. Observe empty Alert at bottom of client window

[andrewmd5]

@FrobtheBuilder it seems this happens whenever there is some kind of error, but in general these modals can just stick around forever instead of dismissing automatically (there definitely should be a way to do that manually.)