Properties of an exposed Rectangle can't be changed in property view

• Add Item to the scene
• Add Rectangle to the scene as the child of the previous Item
• Right click on Item in navigator and choose "Create Component"
• Click OK
• Right click on Item in navigator and choose "Edit Component"
• Click the @ sign next to Rectangle on navigator to expose it as alias
• Save the project
• Go back to main file
• Select the Item in navigator
• Change values in the exposed custom properties section

--> Border and Radius fields are disabled and color fields do not affect anything

This is related to property view issues discussed in QDS-15559, but as that report is primarily about performance and in the end the fix there is probably to not show the properties in case there are a lot of them, a separate issue for the actual property issues is warranted.