[Chat] Restore back button to settings screens (#10602)

src/components/dms/MessagesListHeader.tsx

@@ -13,6 +13,7 @@ import {useProfileShadow} from '#/state/cache/profile-shadow'
 import {useModerationOpts} from '#/state/preferences/moderation-opts'
 import {useSession} from '#/state/session'
 import {PreviewableUserAvatar} from '#/view/com/util/UserAvatar'
+import {useIsWithinSplitView} from '#/screens/Messages/components/splitView/context'
 import {atoms as a, useTheme} from '#/alf'
 import {AvatarBubbles} from '#/components/AvatarBubbles'
 import {ButtonIcon} from '#/components/Button'
@@ -31,13 +32,16 @@ const PFP_SIZE = IS_WEB ? 40 : Layout.HEADER_SLOT_SIZE
 export function MessagesListHeader({convo}: {convo?: ConvoWithDetails | null}) {
   const t = useTheme()
   const moderationOpts = useModerationOpts()
+  const {isWithinSplitView} = useIsWithinSplitView()
 
   return (
     <Layout.Header.Outer noBottomBorder={IS_LIQUID_GLASS}>
       <View style={[a.w_full, a.flex_row, a.gap_xs, a.align_start]}>
-        <View style={[{minHeight: PFP_SIZE}, a.justify_center]}>
-          <Layout.Header.BackButton />
-        </View>
+        {!isWithinSplitView && (
+          <View style={[{minHeight: PFP_SIZE}, a.justify_center]}>
+            <Layout.Header.BackButton />
+          </View>
+        )}
         {convo && moderationOpts ? (
           convo.kind === 'direct' ? (
             <ProfileHeaderReady convo={convo} moderationOpts={moderationOpts} />