Reloading with sample data selected changes my layout

[jtbandes]

Tested with web build.

Steps:

• Load sample dataset, which creates a new layout
• Open layouts sidebar, delete the new layout, select a different layout
• Reload the page

Expected:

• The most recently selected layout is used

Actual:

• The demo dataset is loaded again and the app adds & switches to a new copy of the demo layout, overwriting my most recent layout selection (because of the ?ds=sample-nuscenes in the url)

[jhurliman]