(aws-apigateway): CDK will allow x-region lambda integration that APIG always fails for

### What is the problem?

In CDK Someone can model an application where an API Gateway lambda integration points to a lambda in a region different than the api gateway endpoint. APIG will even instantiate these, requests won't succeed though.

APIG will fail w/
Execution failed due to configuration error: Functions from 'us-west-2' are not reachable in this region ('us-east-1')

CDK should prevent users from shooting themselves in the foot wherever possible, build time error are easier to catch than runtime error.

### Reproduction Steps

```ts
let integration = new LambdaIntegration(lambda.Function.fromFunctionArn(this, "TenantFunction", `someARNFromADifferentRegion`));

const api = new RestApi(this, `TenantAPI`, {
defaultIntegration: integration
});
```

### What did you expect to happen?

CDK build to fail

### What actually happened?

CDK Build Succeeds, CloudFormation synth succeeds

### CDK CLI Version

1.131.0 (build 7560c79)

### Framework Version

_No response_

### Node.js Version

v12.22.5

### OS

OSx

### Language

Typescript

### Language Version

_No response_

### Other information

_No response_

Start at the LambdaIntegration path used with RestApi and the Function.fromFunctionArn example, tracing how the referenced function region is handled during CDK build or CloudFormation synth. Reproduce the cross-region case from the issue and make the build fail for an API Gateway integration whose Lambda is in another region; verify that same-region integrations still synthesize successfully.

Written by the indexing model from the issue text.