Bug: Fn::GetAtt fails to resolve correctly

### Description:

I am trying to use the GetAtt intrinsic function to retrieve the UserPoolId and ClientId from a UserPoolClient and UserPool resource respectively.

Debug output shows
```
Unable to resolve property UserPoolId: OrderedDict([('Fn::GetAtt', ['UserPool', 'UserPoolId'])]). Leaving as is.
```
Is this a supported feature currently or an area where Intrinsic Function support is limited?

If the latter, it would be great to document these limitations somewhere (unless I have missed them!)

### Steps to reproduce:

Run `sam local invoke my_func` where some properties in template.yaml rely on Fn::GetAtt.

### Observed result:

### Expected result:

!GetAtt should return the specified attribute for the given resource.

### Additional environment details (Ex: Windows, Mac, Amazon Linux etc)

1. OS: Linux
2. `sam --version`: SAM CLI, version 1.113.0
3. AWS region: us-east-2

```
# Paste the output of `sam --info` here
{
"version": "1.113.0",
"system": {
"python": "3.11.8",
"os": "Linux-6.8.1-arch1-1-x86_64-with-glibc2.39"
},
"additional_dependencies": {
"docker_engine": "25.0.4",
"aws_cdk": "Not available",
"terraform": "Not available"
},
"available_beta_feature_env_vars": [
"SAM_CLI_BETA_FEATURES",
"SAM_CLI_BETA_BUILD_PERFORMANCE",
"SAM_CLI_BETA_TERRAFORM_SUPPORT",
"SAM_CLI_BETA_RUST_CARGO_LAMBDA"
]
}
```

`Add --debug flag to command you are running`