Issue 25239 - Fix for code intel prompt errors while diffing files in split mode

Created by: subhash686

Closes Issue - https://github.com/sourcegraph/sourcegraph/issues/25239

Test plan

Tested visually,

• launched comparison in split mode
• hovered on code elements on both "base" and "head" sides
• code intel prompt apperead at right line and space.

Working code intel prompt - "base" side of comparison

Working code intel prompt - "head" side of comparison

Element property that needed changing "data-split-mode"