[FIX] point_of_sale: actionpad layout in safari

Tested in safari, chrome and firefox, removing display: flex property
in the .pads element solves the issue. There is actually no need to
declare .pads to flex-flow in column direction as div are block
elements, and they laid out in column by default.

X-original-commit: 6389f00598fa6acd991b21f9875d27005b689ec6

addons/point_of_sale/static/src/css/pos.css

@@ -573,8 +573,6 @@ td {
 
 .pos .leftpane .pads {
     border-top: solid 3px rgb(110, 200, 155);
-    display: flex;
-    flex-direction: column;
 }
 
 .pos .leftpane .pads .subpads {