Children of collapsed shape are still displayed on minimap #56
Description
Describe the Bug
When I collapse a shape, its children are still displayed on minimap.
Steps to Reproduce
See codesandbox: https://codesandbox.io/s/fervent-waterfall-n7ci0x?file=/src/index.js
Reported via https://forum.bpmn.io/t/mini-map-shows-inner-objects-when-outer-one-is-collapsed/8984
Expected Behavior
Children should be hidden.
Environment
- Host (Browser/Node version), if applicable: [e.g. MS Edge 18, Chrome 69, Node 10 LTS]
- OS: [e.g. Windows 7]
- Library version: [e.g. 2.0.0]