[118][Discounts] Bug bash 3 - Paint the expanded label over the solid…

… background

Screenshot before the change: https://screenshot.googleplex.com/8D6iQXbxuQQUHCq
After the change: https://screenshot.googleplex.com/BQ6SLyLhhNRDgRy

(cherry picked from commit ac97fd4)

Bug: 1480833
Change-Id: I51370f9fb32d2010f75bbc930dc184fce60e94e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4895258
Reviewed-by: Emily Shack <emshack@chromium.org>
Commit-Queue: Mei Liang <meiliang@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1202935}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4908640
Cr-Commit-Position: refs/branch-heads/5993@{#1107}
Cr-Branched-From: 5113507-refs/heads/main@{#1192594}

chrome/browser/ui/views/autofill/payments/offer_notification_icon_view.cc

@@ -77,6 +77,7 @@ void OfferNotificationIconView::MaybeShowPageActionLabel() {
     return;
   }
   should_extend_label_shown_duration_ = true;
+  SetPaintLabelOverSolidBackground(true);
   AnimateIn(IDS_DISCOUNT_ICON_EXPANDED_TEXT);
   controller->OnIconExpanded();
   SetAccessibilityProperties(