TreeTable expand based on model

OpenUI5 version: 1.89.1

Just like setting any other properties of a row via a model, the expand information should be control-able via the model as well.

I know that there are odataV2 annotations for that, but this does not work for

• JSON Models
• oData V4 Model
• Cases where you add a sub item manually in the model and its parent should be expanded instead of asking the user to add and item and then click on expand on the parent to show the added item.

Will probably require a new class of sap.ui.table.row, one that has the expand as an additional property.

Also it is quite odd at the moment to get from a model property or path to the expand method. You have to first find the row this model element belongs to. Then find the rowindex of that row (expensive?!) and then call expand(rowindex).