### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

I am creating an API Gateway with a Lambda Authorizer via a CloudFormation stack. The stack specifies a data mapping from the request body passed to the API to the request body expected by Kinesis (search `RequestTemplates` in the attached CloudFormation template). It also specifies a model and a validator which are used to validate the request body. Both of these aspects of the API work in AWS itself but appear to be ignored in LocalStack. 

If I test with the same request body I passed to AWS, LocalStack throws an error indicating that the PutRecord call to Kinesis isn't providing a PartitionKey field. The data mapping should've taken care of it. If I then invoke the API in LocalStack with what *should* be sent to Kinesis, the invocation succeeds. This second invocation *should* violate the validation logic in the template, but doesn't. 

### Expected Behavior

The data mapping should correctly map the passed-in request body to a request body which Kinesis can understand. In addition, the validator should reject requests that don't pass validation.

### How are you starting LocalStack?

With a `docker run` command

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

docker run --rm -it -p 4566:4566 -p 4571:4571 -e LOCALSTACK_API_KEY=$env:LOCALSTACK_API_KEY localstack/localstack

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

```
# create s3 bucket and upload c# lambda authorizer zip to s3
aws --endpoint-url=http://localhost:4566 s3api create-bucket --bucket timeseries-ingest-lambda-artifacts
aws --endpoint-url=http://localhost:4566 s3 cp index.zip s3://timeseries-ingest-lambda-artifacts/KinesisAPILambdaAuthorizer/index.zip
# create stream
aws --endpoint-url=http://localhost:4566 kinesis create-stream --stream-name test-timeseries-ingest-stream --shard-count 1
# create stack
aws --endpoint-url=http://localhost:4566 cloudformation create-stack --stack-name test-kinesis-api --template-body file://cloudformation-kinesis-api-resources-PER-ENVIRONMENT.yaml --parameters ParameterKey=AppName,ParameterValue=timeseries-ingest ParameterKey=Environment,ParameterValue=test
```

This is the CloudFormation template: [cloudformation-kinesis-api-resources-PER-ENVIRONMENT.yaml.txt](https://github.com/localstack/localstack/files/7973188/cloudformation-kinesis-api-resources-PER-ENVIRONMENT.yaml.txt)

### Environment

```markdown
- OS: Ubuntu 20.04
- LocalStack: latest (as of 3 days ago)
```


### Anything else?

_No response_
return "%s:%s" % (self.region, self.prefix)
PREDEFINED_ENVIRONMENTS = {ENV_DEV: Environment(region=REGION_LOCAL, prefix=ENV_DEV)}
def get_environment(env=None, region_name=None):
    """
    Return an Environment object based on the input arguments.
    Parameter `env` can be either of:
        * None (or empty), in which case the rules below are applied to (env = os.environ['ENV'] or ENV_DEV)
        * an Environment object (then this object is returned)
        * a string '<region>:<name>', which corresponds to Environment(region='<region>', prefix='<prefix>')
        * the predefined string 'dev' (ENV_DEV), which implies Environment(region='local', prefix='dev')
        * a string '<name>', which implies Environment(region=DEFAULT_REGION, prefix='<name>')
    Additionally, parameter `region_name` can be used to override DEFAULT_REGION.
    """
    if not env:
        if "ENV" in os.environ:
            env = os.environ["ENV"]
        else:
            env = ENV_DEV
    elif not is_string(env) and not isinstance(env, Environment):
        raise Exception("Invalid environment: %s" % env)
    if is_string(env):
        env = Environment.from_string(env)
    if region_name:
        env.region = region_name
    if not env.region:
        raise Exception('Invalid region in environment: "%s"' % env)
    return env
def is_local_env(env):
    return not env or env.region == REGION_LOCAL or env.prefix == ENV_DEV
class Boto3Session(boto3.session.Session):