ui: emoji picker background color fix

Session/Conversations/Emoji Picker/EmojiPickerCollectionView.swift

@@ -60,7 +60,7 @@ class EmojiPickerCollectionView: UICollectionView {
             withReuseIdentifier: EmojiSectionHeader.reuseIdentifier
         )
 
-        backgroundColor = isDarkMode ? .ows_gray90 : .ows_white
+        backgroundColor = .clear
 
         let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(handleLongPress))
         panGestureRecognizer.require(toFail: longPressGesture)

Session/Conversations/Emoji Picker/EmojiPickerSheet.swift

@@ -22,7 +22,7 @@ class EmojiPickerSheet: BaseVC {
     private lazy var searchBar: SearchBar = {
         let result = SearchBar()
         result.tintColor = Colors.text
-        result.backgroundColor = isDarkMode ? .ows_gray90 : .ows_white
+        result.backgroundColor = .clear
         result.delegate = self
         return result
     }()

Session/Conversations/Emoji Picker/EmojiSkinTonePicker.swift

@@ -116,12 +116,12 @@ class EmojiSkinTonePicker: UIView {
         layer.shadowOpacity = 0.25
         layer.shadowRadius = 4
 
-        referenceOverlay.backgroundColor = isDarkMode ? .ows_gray75 : .ows_white
+        referenceOverlay.backgroundColor = Colors.modalBackground
         referenceOverlay.layer.cornerRadius = 9
         addSubview(referenceOverlay)
 
         containerView.layoutMargins = UIEdgeInsets(top: 9, leading: 16, bottom: 9, trailing: 16)
-        containerView.backgroundColor = isDarkMode ? .ows_gray75 : .ows_white
+        containerView.backgroundColor = Colors.modalBackground
         containerView.layer.cornerRadius = 11
         addSubview(containerView)
         containerView.autoPinWidthToSuperview()