<!-- Love localstack? Please consider supporting our collective:
👉  https://opencollective.com/localstack/donate -->

# Type of request: This is a ...

[ x ] bug report
[ ] feature request

# Detailed description

When I try to list stacks and filter the stack status, it lists all the stacks rather than filter them out.

I saw someone had this issue before and was meant to be fixed, but doesnt seem like its fixed:
- https://github.com/localstack/localstack/issues/2698

## Expected behavior

Stacks should be filtered


## Actual behavior

All stacks are returned

# Steps to reproduce

Run latest docker version of localstack.
Create new stack
Try to run something like:
aws --endpoint-url=http://localhost:4566 cloudformation list-stacks --stack-status-filter DELETE_FAILED

It will return all stacks when it should return an empty list

## Command used to start LocalStack
docker run --network host -d -e DEFAULT_REGION="eu-west-1" localstack/localstack:latest

## Client code (AWS SDK code snippet, or sequence of "awslocal" commands)
aws --endpoint-url=http://localhost:4566 cloudformation list-stacks --stack-status-filter DELETE_FAILED

Using boto3, the same thing happens:
response = self.__cloudformation_client.list_stacks(StackStatusFilter=['CREATE_FAILED'])

...

state = CloudFormationRegion.get()
    result = {'Exports': {'member': state.exports}}
    return result
def list_imports(req_params):
    state = CloudFormationRegion.get()
    export_name = req_params.get('ExportName')
    importing_stack_names = []
    for stack in state.stacks.values():
        if export_name in stack.imports:
            importing_stack_names.append(stack.stack_name)
    result = {'Imports': {'member': importing_stack_names}}
    return result
def validate_template(req_params):
    try:
        result = template_preparer.validate_template(req_params)
        result = '<tmp>%s</tmp>' % result
        result = xmltodict.parse(result)['tmp']
        return result
    except Exception as err:
        return error_response('Template Validation Error: %s' % err)
def describe_stack_events(req_params):