Actually disable Wallet card saving on Linux.

chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc

Index: chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc
diff --git a/chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc b/chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc
index e49e0b87cec0712b98cf14b976ab7603099706df..d460e73a7aba4a69628e8f0cc3d716effd105a9d 100644
--- a/chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc
+++ b/chrome/browser/ui/views/autofill/card_unmask_prompt_views.cc
@@ -328,7 +328,8 @@ void CardUnmaskPromptViews::AnimationProgressed(
     const gfx::Animation* animation) {
   uint8_t alpha = static_cast<uint8_t>(animation->CurrentValueBetween(0, 255));
   progress_overlay_->SetAlpha(alpha);
-  storage_row_->SetAlpha(255 - alpha);
+  if (storage_row_)
+    storage_row_->SetAlpha(255 - alpha);
 }
 
 void CardUnmaskPromptViews::InitIfNecessary() {