### 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/
target_uri = invocation_uri % (aws_stack.get_region(), lambda_uri)
        result = testutil.connect_api_gateway_to_http_with_lambda_proxy(
            "test_gateway2", target_uri, path=path, stage_name=self.TEST_STAGE_NAME
        )
        api_id = result["id"]
        path_map = get_rest_api_paths(api_id)
        _, resource = get_resource_for_path(path, path_map)
        
        path_with_replace = path.replace("{test_param1}", "foo1")
        path_with_params = path_with_replace + "?foo=foo&bar=bar&bar=baz"
        url = gateway_request_url(
            api_id=api_id, stage_name=self.TEST_STAGE_NAME, path=path_with_params
        )
        
        data = {"return_status_code": 203, "return_headers": {"foo": "bar123"}}
        if data_mutator_fn:
            assert callable(data_mutator_fn)
            data_mutator_fn(data)
        result = requests.post(
            url,
            data=json.dumps(data),
            headers={"User-Agent": "python-requests/testing"},
        )
        return ApiGatewayLambdaProxyIntegrationTestResult(
            data=data,
            resource=resource,
            result=result,
            url=url,
            path_with_replace=path_with_replace,
        )