(hotswap): make appsync FunctionConfiguration hotswap capable

### Describe the feature

It would be great if the AWS::AppSync::FunctionConfiguration Code could be hot swapped

### Use Case

Ease of development of JS resolvers

### Proposed Solution

Make the code of a AWS::AppSync::FunctionConfiguration hotswappable

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### CDK version used

2.89.0

### Environment details (OS name and version, etc.)

macOS