Change position of all cells in Grid to 'relative'

[PreslavKozovski]

Describe the bug

The following style - https://github.com/telerik/kendo-themes/blob/develop/packages/default/scss/grid/_layout.scss#L356

Should affect all cells.

The JavaScript expects that it can add the "dirty" indicator without adding the ".k-dirty-cell" to the cell.

To reproduce
Steps to reproduce the behavior:

1. Go to https://demos.telerik.com/kendo-ui/grid/editing-popup
2. Click edit on any non-first row.
3. Edit a record.
4. The "dirty" indicator is shown over the first cell of the Grid.

Screenshots

Affected package (please provide)

• theme-default
• theme-bootstrap
• theme-material

Affected suites (please provide)

• Kendo UI for jQuery
• Kendo UI for Angular
• Kendo UI for React
• Kendo UI for Vue
• Telerik UI for Blazor

Affected browsers (please provide)

• all

[PreslavKozovski]

Before fixing this, we should implement - #1276

[Alex-Bubblemaster]

Reported in ticket 1455833