### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

When creating base-path-mappings on an API Gateway, there is a special `(none)` path when you don't specify a path during creation. Localstack stores this as `basePath: "(none)"` internally.
When you query to get the base paths, the URLs are escaped by the client (verified in both awscli and terraform) so the basePath is sent as `%28none%29` in the url.
Localstack doesn't appear to be decoding urls and when you attempt to get-base-path-mapping it fails in a string comparison of `(none)` to `%28none%29`.

```shell
> aws --endpoint-url=http://localhost:4566 apigateway get-base-path-mapping --domain-name example.com --base-path "(none)"

An error occurred (NotFoundException) when calling the GetBasePathMapping operation: Base path mapping not found: %28none%29
```

### Expected Behavior

When you attempt to get-base-path-mappings after creating one with the (none) path, it succeeds and returns the mapping.

```
> aws --endpoint-url=http://localhost:4566 apigateway get-base-path-mapping --domain-name example.com --base-path "(none)"

{
    "basePath": "(none)",
    "restApiId": "uyy4c3dsho",
    "stage": "dev"
}
```


### How are you starting LocalStack?

With the `localstack` script

### Steps To Reproduce

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

    make start

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

    awslocal apigateway create-rest-api --name "testgw"
    awslocal apigateway create-base-path-mapping --domain-name example.com --rest-api-id <from output above> --stage dev
    awslocal apigateway get-base-path-mapping --domain-name example.com --base-path "(none)"



### Environment

```markdown
- OS: fedora 34
- LocalStack: latest
```


### Anything else?

https://docs.aws.amazon.com/apigateway/api-reference/link-relation/basepathmapping-by-base-path/
pass_through_behavior=payload.get("passthroughBehavior"),
                request_templates=payload.get("requestTemplates") or {},
            )
            integration.create_integration_response(
                status_code=payload.get("responses", {}).get("default", {}).get("statusCode", 200),
                selection_pattern=None,
                response_templates=None,
                content_handling=None,
            )
            child.resource_methods[m]["methodIntegration"] = integration
        rest_api.resources[child_id] = child
        return child
    basepath_mode = (query_params.get("basepath") or ["prepend"])[0]
    base_path = (body.get("basePath") or "") if basepath_mode == "prepend" else ""
    for path in body.get("paths", {}):
        get_or_create_path(base_path + path)
    policy = body.get("x-amazon-apigateway-policy")
    if policy:
        policy = json.dumps(policy) if isinstance(policy, dict) else str(policy)
        rest_api.policy = policy
    minimum_compression_size = body.get("x-amazon-apigateway-minimum-compression-size")
    if minimum_compression_size is not None:
        rest_api.minimum_compression_size = int(minimum_compression_size)
    endpoint_config = body.get("x-amazon-apigateway-endpoint-configuration")
    if endpoint_config:
        if endpoint_config.get("vpcEndpointIds"):
            endpoint_config.setdefault("types", ["PRIVATE"])
        rest_api.endpoint_configuration = endpoint_config
    return rest_api