Fulfillment Lambda fails to update version/alias when Embedding settings change on stack update

[ihmaws]

Describe the bug
Fulfillment Lambda fails to update version/alias when Embedding settings change on stack update (credit to @rstrahan on reporting this bug)

To Reproduce

1. Create new stack from here: https://solutions-reference.s3.amazonaws.com/qnabot-on-aws/v5.3.0/qnabot-on-aws-main.template
2. Set parameter EmbeddingsApi to SageMaker
3. Deploy stack
4. Once complete, import questions, and run query through client (should be successful)
5. Update stack and set EmbeddingsApi to Disabled
6. Once complete, run query again through client (should be successful)
7. Update stack and set parameter EmbeddingsApi to SageMaker
8. Once complete, run query again through client (this time should fail)

Expected behavior
When enabling, disabling, and then reenabling embeddings, the client queries should still work.

Please complete the following information about the solution:

• [v5.3.0] Version: [e.g. v0.0.1]
• [us-east-1] Region: [e.g. us-east-1]
• [No] Was the solution modified from the version published on this repository?
• [N/A] If the answer to the previous question was yes, are the changes available on GitHub?
• [N/A] Have you checked your service quotas for the sevices this solution uses?
• [Yes] Were there any errors in the CloudWatch Logs?

{
"errorType": "AccessDeniedException",
"errorMessage": "User: arn:aws:sts::XXXXXX:assumed-role/v530-qnabot-FulfillmentLambdaRole/v530-qnabot-FulfillmentLambda is not authorized to perform: sagemaker:InvokeEndpoint on resource: arn:aws:sagemaker:us-east-1:XXXXXX:endpoint/qnabotsmprovisionedembeddingendpoint because no identity-based policy allows the sagemaker:InvokeEndpoint action",
"code": "AccessDeniedException",
...
}

Screenshots
Lambda Console - new lambda version has not been created, despite 2 lambda updates:

Empty response in client due to lambda failure:

Additional context
Temporary workaround is to manually point the live alias to $LATEST

[ihmaws]

Fixed as of v5.3.1