Revert "Fix merge conflict"

This reverts commit 7f1e61b7b8b6c6bb76ac5b99be8c762e1b01cd5e.

These icons were renamed, but the original icons are now restored so those changes need to be reverted.

Contributes to issue CURA-8267.

resources/themes/cura-light/styles.qml

@@ -76,7 +76,7 @@ QtObject
                     height: UM.Theme.getSize("standard_arrow").height
                     sourceSize.height: width
                     color: control.enabled ? UM.Theme.getColor("setting_control_button") : UM.Theme.getColor("setting_category_disabled_text")
-                    source: UM.Theme.getIcon("ChevronSingleDown")
+                    source: UM.Theme.getIcon("arrow_bottom")
                 }
                 Label
                 {