Debug Console output remains on screen after closing VR Preview if "Debug in stereo layer' is enabled

Affects VR Preview in Editor

Reproduced in 4.18.3 CL 3832480 and 4.19 P1 CL 3837072

1. Create new, blank project with no starter content
2. Open Project Settings, navigate to Rendering > VR > Debug Canvas in Layer, set Debug Canvas in Layer = true
3. Start VR Preview
4. Press ~ key/ open debug canvas
5. Close VR Preview
6. Start VR Preview again

Result: Everything from the Canvas layer remains above the image until the editor is restarted

Expected: Debug canvas is cleared when the VR Preview is closed