Issue with sm-ssh-ide in SageMaker Unified Studio

## Description
SageMaker Unified Studio is GA release, And I encountered issues with `sm-ssh-ide configure --ssh-only` command.

1. Permission and Shell Initialization Issues:
```bash
sm-ssh-ide: Configuring services...
/usr/local/bin/_activate_current_env.sh: line 8: : command not found
critical libmamba Shell not initialized
```

The command fails with permission errors when trying to access `/home/sagemaker-user`:
```bash
find: Failed to change directory: /home/sagemaker-user: Permission denied
find: Failed to restore initial working directory: /home/sagemaker-user: Permission denied
```

2. IAM Role Conflicts:
Following the IAM setup instructions from [IAM_SSM_Setup.md](https://github.com/aws-samples/sagemaker-ssh-helper/blob/main/IAM_SSM_Setup.md) creates problematic role configurations. The provided scripts cause role assumption failures and permission conflicts. This makes it impossible to properly assume roles in the Studio environment.

## Environment
- SageMaker Unified Studio (GA version)
- Default Studio environment
- Following official documentation and IAM setup guide

## Expected Behavior
- `sm-ssh-ide configure` should complete successfully
- IAM roles should work correctly without assumption conflicts

## Actual Behavior
- Shell initialization fails
- Permission denied errors for `/home/sagemaker-user`
- IAM role assumption fails after applying the recommended IAM setup

Could you please provide guidance on:
1. Correct permission setup for Unified Studio
2. Updated IAM configuration that doesn't break role assumption
3. Proper shell initialization process for the new Studio environment