Update property sheet for Rectangle to include independent radii

https://doc.qt.io/qt-6/qml-qtquick-rectangle.html

According to the documentation
Properties

• antialiasing : bool
• border
  • border.color : color
  • border.pixelAligned : bool
  • border.width : int
• bottomLeftRadius : real (since 6.7)
• bottomRightRadius : real (since 6.7)
• color : color
• gradient : var
• radius : real
• topLeftRadius : real (since 6.7)
• topRightRadius : real (since 6.7)