fix: add conditional rendering for mcp_tool_id and update mcp_source assignment logic

Author: liuruibin

ui/src/workflow/nodes/ai-chat-node/index.vue

@@ -137,7 +137,9 @@
             chat_data.mcp_tool_id || (chat_data.mcp_servers && chat_data.mcp_servers.length > 0)
           "
         >
-          <div class="flex-between border border-r-6 white-bg mb-4" style="padding: 5px 8px">
+          <div class="flex-between border border-r-6 white-bg mb-4" style="padding: 5px 8px"
+            v-if="relatedObject(mcpToolSelectOptions, chat_data.mcp_tool_id, 'id')"
+          >
             <div class="flex align-center" style="line-height: 20px">
               <el-avatar
                 v-if="relatedObject(mcpToolSelectOptions, chat_data.mcp_tool_id, 'id')?.icon"

ui/src/workflow/nodes/mcp-node/index.vue

@@ -531,7 +531,7 @@ onMounted(() => {
       set(props.nodeModel.properties.node_data, 'is_result', true)
     }
   }
-  if (props.nodeModel.properties.node_data.mcp_servers) {
+  if (props.nodeModel.properties.node_data.mcp_servers && !props.nodeModel.properties.node_data.mcp_source) {
     set(props.nodeModel.properties.node_data, 'mcp_source', 'custom')
   }
   getMcpToolSelectOptions()