CCA: Fix 3x3, 4x4 grid line not transit when on/off toggle

Bug: b/176266123
Test: Manually test grid line transition animatation when toggling and
change grid type in grid setting.

Change-Id: I91653609c0eea082de8091bc1b45a8a1f301d6d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2626695
Commit-Queue: Inker Kuo <inker@chromium.org>
Commit-Queue: Shik Chen <shik@chromium.org>
Auto-Submit: Inker Kuo <inker@chromium.org>
Reviewed-by: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842885}

chromeos/components/camera_app_ui/resources/css/main.css

@@ -955,7 +955,7 @@ body:not(.expert) #settings-expert {
   transform: translateY(-50%);
 }
 
-body.grid-4x4 #preview-grid-horizontal::before {
+body.grid.grid-4x4 #preview-grid-horizontal::before {
   border-bottom: 1px solid white;
   content: '';
   height: 0;
@@ -965,7 +965,7 @@ body.grid-4x4 #preview-grid-horizontal::before {
   top: 0;
 }
 
-body.grid-3x3 #preview-grid-horizontal,
+body.grid.grid-3x3 #preview-grid-horizontal,
 body.view-grid-settings.grid-3x3 #preview-grid-horizontal {
   height: 33.333%;
 }