[Chat] Fix assumption that every chat has an owner (#10373)

src/components/dms/util.ts

@@ -69,7 +69,7 @@ export type ConvoWithDetails = {view: ChatBskyConvoDefs.ConvoView} & (
   | {
       kind: 'group'
       details: $Typed<ChatBskyConvoDefs.GroupConvo>
-      primaryMember: GroupConvoMember // the owner
+      primaryMember?: GroupConvoMember // the owner - may have left, thus optional
       members: Array<GroupConvoMember>
     }
   | {
@@ -117,11 +117,6 @@ export function parseConvoView(
       }
     }
 
-    if (!owner) {
-      logger.warn('No owner found in group convo')
-      return null
-    }
-
     return {
       view: convoView,
       kind: 'group',