Add active class to the column menu icon once something in it is different from default

Currently we recommend using custom class on the header(https://www.telerik.com/kendo-vue-ui/components/grid/columns/column-menu/#toc-styling-the-column-menu-icon), yet not visualising that the menu is populated seems like a UI misleading issue when using the component so we should add it by default

Describe the bug
Locked and resized columns leave a small gap between the columns when scrolling is performed

To Reproduce
Steps to reproduce the behavior:
https://stackblitz.com/edit/mzxqs7-hy29kw?file=src%2Fmain.vue
lock both first and the second column from the column menu
resize the first column
scroll the columns

Curent -
A tiny gap is visible between the first and the second column