[Code Editor] External browser authentication popup bar missing in image 3.6.1+

### Product Version

- [ ] Amazon SageMaker Studio Classic
- [ ] Amazon SageMaker Studio
- [ ] Issue is not related to SageMaker Studio

### Issue Description

Browser authentication for Snowflake (and other external services) is not working in SageMaker Code Editor with recent images (3.6.1+).

In older images (3.4.1), a popup bar appeared allowing users to paste the authentication redirect URL. This popup bar no longer appears in newer images.

## Steps to Reproduce

1. Launch SageMaker Code Editor with image 3.6.1
2. Run Python code with Snowflake connector using `authenticator='externalbrowser'`
3. Expected: Popup bar appears to paste the authentication URL
4. Actual: No popup bar appears

## Working Version
- Image 3.4.1

## Broken Version
- Image 3.6.1

### Expected Behavior

_No response_

### Observed Behavior

_No response_

### Product Category

_No response_

### Feedback Category

_No response_

### Other Details

_No response_

No repository files or tests are identified. Start by reproducing the issue in SageMaker Code Editor image 3.6.1 with Python code using the Snowflake connector and authenticator='externalbrowser', then compare it with image 3.4.1. Done means the authentication popup bar appears again and accepts the redirect URL.

Written by the indexing model from the issue text.