Simplify chat margins (#10334)

src/components/dms/DateDivider.tsx

@@ -56,7 +56,7 @@ let DateDivider = ({date: dateStr}: {date: string}): React.ReactNode => {
   }
 
   return (
-    <View style={[a.w_full, a.my_sm]}>
+    <View style={[a.w_full, a.mt_md]}>
       <Text
         style={[
           a.text_xs,

src/components/dms/MessageItem.tsx

@@ -404,8 +404,7 @@ let MessageItem = ({
           <DateDivider date={message.sentAt} />
         </Animated.View>
       )}
-      <View
+      <View style={[messageInset, effectiveFirstInCluster && a.mt_md]}>
-        style={[messageInset, isFirstInCluster && !showDateDivider && a.mt_sm]}>
         <View style={[a.relative]}>
           {showAvatar ? (
             <View

src/components/dms/SystemMessageItem.tsx

@@ -28,7 +28,6 @@ export function SystemMessageItem({
         a.justify_center,
         a.px_md,
         a.mt_md,
-        a.mb_xs,
       ]}>
       <Icon size="xs" style={[a.mr_2xs, t.atoms.text_contrast_medium]} />
       <Text