Models tree: Locate ECInstance in hierarchy when it's selected in unified selection

[grigasp]

Request: When an element is selected in the viewport, expand the model tree and highlight that element node.

UX questions:

• Are we expected to scroll to the newly located node? What if multiple ECInstances are selected and they're in different locations of the hierarchy?
• What if the ECInstance is located in a very large hierarchy level that we're not going to load (size limit exceeded)?
• Do we want to collapse other hierarchy levels?

[grigasp]

Closing in favor of https://github.com/iTwin/viewer-components-react/issues/788