[kcms/users]: Make sure avatar grid doesn't escape bounds

This adds the column spacing into calculation for determining how many columns there are, preventing certain multiples of window sizes from having too many columns.

BUG: 428899

kcms/users/package/contents/ui/UserDetailsPage.qml

@@ -256,7 +256,8 @@ SimpleKCM {
                     rowSpacing: Kirigami.Units.smallSpacing
                     columnSpacing: Kirigami.Units.smallSpacing
                     columns: {
-                        return Math.floor((stackSwitcher.width) / (Kirigami.Units.gridUnit * 6))
+                        // subtract gridunit from stackswticher width to roughly compensate for slight overlap on tightly fit grids
+                        return Math.floor((stackSwitcher.width - Kirigami.Units.gridUnit) / ((Kirigami.Units.gridUnit * 6) + picturesColumn.columnSpacing))
                     }
 
                     Layout.fillWidth: true