Fix: chat/agent -- Default avatar is not displaying correctly. (#15948)

### What problem does this PR solve?

Fix: chat/agent -- Default avatar is not displaying correctly.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/components/message-item/index.tsx

@@ -51,6 +51,7 @@ const MessageItem = ({
   showLikeButton = true,
   showLoudspeaker = true,
   visibleAvatar = true,
+  nickname,
 }: IProps) => {
   const { theme } = useTheme();
   const isAssistant = item.role === MessageType.Assistant;
@@ -98,6 +99,7 @@ const MessageItem = ({
                 className="size-10"
                 avatar={avatar ?? '/logo.svg'}
                 isPerson
+                name={nickname}
               />
             ) : avatarDialog ? (
               <RAGFlowAvatar

web/src/components/next-message-item/index.tsx

@@ -79,6 +79,7 @@ function MessageItem({
   children,
   showLog,
   isShare,
+  nickname,
 }: IProps) {
   const { theme } = useTheme();
   const isAssistant = item.role === MessageType.Assistant;
@@ -186,7 +187,11 @@ function MessageItem({
         >
           {visibleAvatar &&
             (item.role === MessageType.User ? (
-              <RAGFlowAvatar avatar={avatar ?? '/logo.svg'} />
+              <RAGFlowAvatar
+                avatar={avatar ?? '/logo.svg'}
+                name={nickname}
+                isPerson
+              />
             ) : avatarDialog || agentName ? (
               <RAGFlowAvatar
                 avatar={avatarDialog as string}