Fix: After deleting all conversation lists, the chat input box can still be used for input. #4907 (#4909)

### What problem does this PR solve?

Fix: After deleting all conversation lists, the chat input box can still
be used for input. #4907

### Type of change

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

web/src/utils/llm-util.ts

@@ -0,0 +1,13 @@
+export const getLLMIconName = (fid: string, llm_name: string) => {
+  if (fid === 'FastEmbed') {
+    return llm_name.split('/').at(0) ?? '';
+  }
+
+  return fid;
+};
+
+export const getLlmNameAndFIdByLlmId = (llmId?: string) => {
+  const [llmName, fId] = llmId?.split('@') || [];
+
+  return { fId, llmName };
+};