[ConsentV2] Truncate the consent content with ellipsis

This CL truncate the content to have a maximum of 2 lines with ellipsis
at the end.

(cherry picked from commit 358b119)

Bug: 1298116, 1302728
Change-Id: I11e378cc67851cb0973a5a60d2b3896ed027341d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3503948
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Commit-Queue: Mei Liang <meiliang@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#977821}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3510947
Cr-Commit-Position: refs/branch-heads/4896@{#395}
Cr-Branched-From: 1f63ff4-refs/heads/main@{#972766}

chrome/browser/resources/new_tab_page/modules/cart/discount_consent_card.html

@@ -60,6 +60,14 @@
     width: 220px;
   }
 
+  .truncate {
+    -webkit-box-orient: vertical;
+    -webkit-line-clamp: 2;
+    display: -webkit-box;
+    overflow: hidden;
+    text-overflow: ellipsis;
+  }
+
   .button-container {
     display: inline-block;
     margin-block-end: 16px;
@@ -99,7 +107,7 @@
       <template id="consentStepRepeat" is="dom-repeat" items="[[steps_]]"
           as="step">
         <div class="step-container" id="[[step.id]]">
-          <div class="content-container">
+          <div class="content-container truncate">
             <span class="content">
               [[step.content]]
             </span>