(OpenSearch): (Unable to update stack to reflect index changes)

### Describe the bug

I have a OpenSearch Serverless resource defined through the GenAI CDK Constructs, including a index
If I try to change the definition of the index, say by adding one new mapping, and run `cdk deploy`, I get an error saying **Update not supported**. An additional problem is that the stack is unable to rollback the changes, apparently due to another issue, so that I am forced to delete and recreate the stack

I attached two snapshots, one for the failed update and another for the failed rollback

### Expected Behavior

Update to complete successfully

### Current Behavior

Update and further rollback failed, leaving the stack in a inconsistent state

### Reproduction Steps

For an existing stack, add one new mapping to a *VectorIndex* resource and run `cdk deploy`

### Possible Solution

_No response_

### Additional Information/Context

_No response_

### CDK CLI Version

2.135.0

### Framework Version

_No response_

### Node.js Version

v21.7.1

### OS

MacOS

### Language

Python

### Language Version

_No response_

### Region experiencing the issue

us-east-1

### Code modification

.

### Other information

_No response_

### Service quota

- [X] I have reviewed the service quotas for this construct