A previous commit (via gitea#29638) changed the `.repository .data-table
.tr` CSS rule to forcibly override the background to `none`. This, in
turn, disabled the even-odd row coloring.
Doing so should be a preference of the theme used, and should not be
enforced by the core CSS rules. This patch removes the override.
Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>