feat(grid): Add styling for column selection checkboxes telerik/kendo#7097

Author: theOrlin

styles/web/type-material.less

@@ -3967,8 +3967,7 @@ div.k-scheduler-marquee:after {
 @spreadsheet-page-orientation-border-color: @widget-border-color;
 
 .k-grid {
-    .k-edit-cell input.k-checkbox,
-    .k-grid-edit-row input.k-checkbox {
+    input.k-checkbox {
         margin-top: 5px;
         width: 16px;
         height: 16px;

styles/web/type-nova.less

@@ -2236,8 +2236,7 @@ html .km-pane-wrapper .km-widget,
 @spreadsheet-page-orientation-border-color: lighten(@hover-text-color, 8%);
 
 .k-grid {
-    .k-edit-cell input.k-checkbox,
-    .k-grid-edit-row input.k-checkbox {
+    input.k-checkbox {
         width: 16px;
         height: 17px;
     }