### 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/
)
        # STEP 
        _prepare_method_integration(
            integr_kwargs={
                "requestTemplates": {
                    "application/json": """
                    #set($data = $util.escapeJavaScript($input.json('$')))
                    {"input": "$data","stateMachineArn": "%s"}
                    """
                    % sm_arn
                }
            }
        )
        # invok
        client.create_deployment(restApiId=rest_api["id"], stageName="dev")
        url = gateway_request_url(api_id=rest_api["id"], stage_name="dev", path="/")
        test_data = {"test": "test-value"}
        resp = requests.post(url, data=json.dumps(test_data))
        self.assertEqual(200, resp.status_code)
        self.assertIn("executionArn", resp.content.decode())
        self.assertIn("startDate", resp.content.decode())
        # STEP 
        _prepare_method_integration(overwrite=True)
        test_data_1 = {
            "input": json.dumps(test_data),
            "name": "MyExecution",
            "stateMachineArn": sm_arn,
        }
        # invok
        resp = requests.post(url, data=json.dumps(test_data_1))