Do not reload UI if the Reading List entry does not exist

ios/chrome/browser/ui/reading_list/reading_list_empty_collection_background.mm

Index: ios/chrome/browser/ui/reading_list/reading_list_empty_collection_background.mm
diff --git a/ios/chrome/browser/ui/reading_list/reading_list_empty_collection_background.mm b/ios/chrome/browser/ui/reading_list/reading_list_empty_collection_background.mm
index 4c8ac939e7a690043bb49ae6864970346115c002..7b7e1414f233f9f1c015411bd5f23192e2f9e0f9 100644
--- a/ios/chrome/browser/ui/reading_list/reading_list_empty_collection_background.mm
+++ b/ios/chrome/browser/ui/reading_list/reading_list_empty_collection_background.mm
@@ -64,6 +64,8 @@ const CGFloat kPercentageFromTopForPosition = 0.4;
 
 @implementation ReadingListEmptyCollectionBackground
 
+#pragma mark - Public
+
 - (instancetype)init {
   self = [super initWithFrame:CGRectZero];
   if (self) {
@@ -172,6 +174,8 @@ const CGFloat kPercentageFromTopForPosition = 0.4;
     label.numberOfLines = 0;
     label.textAlignment = NSTextAlignmentCenter;
     label.accessibilityLabel = accessibilityLabel;
+    label.accessibilityIdentifier =
+        [ReadingListEmptyCollectionBackground accessibilityIdentifier];
     [label setTranslatesAutoresizingMaskIntoConstraints:NO];
     [self addSubview:label];
 
@@ -185,6 +189,12 @@ const CGFloat kPercentageFromTopForPosition = 0.4;
   return self;
 }
 
++ (NSString*)accessibilityIdentifier {
+  return @"ReadingListBackgroundViewIdentifier";
+}
+
+#pragma mark - Private
+
 - (void)attachIconNamed:(NSString*)iconName
                toString:(NSMutableAttributedString*)instructionString
               withCaret:(NSMutableAttributedString*)caret