Unable to use the import operation on the admin endpoint of a tile service in ArcGIS Online.

Workaround

1. In ArcGIS Pro, in the Contents pane, right-click the layer > Sharing > Share As Web Layer.
2. In the Share As Web Layer pane, on the General tab, for Layer Type, select Vector Tile.
3. On the Configuration tab, for Caching, select Cache locally.
4. Click Analyze > Publish.

Steps to Reproduce