Empty stage in API Gateway output for endpoints

还没有人认领这个 Issue。

With this `serverless.yml`:

```
service: scraperator
frameworkVersion: "3"
provider:
name: aws
runtime: python3.9
stage: local
region: us-east-1
logs:
httpApi: true
deploymentBucket:
name: serverless-deploys
serverSideEncryption: AES256
httpApi:
cors: true
disableDefaultEndpoint: false
plugins:
- serverless-python-requirements
- serverless-localstack
custom:
stage: ${opt:stage, self:provider.stage}
localstack:
stages:
- local
autostart: false
functions:
config:
handler: capture.config
events:
- httpApi:
method: GET
path: /config
capture:
handler: capture.handler
events:
- httpApi:
method: POST
path: /capture
```

A successful deploy yields this output:

```
endpoints:
GET - https://746fbc6e.execute-api.localhost.localstack.cloud:4566//config
POST - https://746fbc6e.execute-api.localhost.localstack.cloud:4566//capture
```

Note the `//` where there should be `/local/`.
The URL as printed does not work. However, removing a `/` (e.g. https://746fbc6e.execute-api.localhost.localstack.cloud:4566/config) does work.

使用提供的 serverless.yml 重新执行部署，并将打印出的端点 URL 与 issue 中描述的可用 URL 进行比较。跟踪 Serverless 插件如何格式化 API Gateway 端点路径，然后验证已部署的端点包含配置的本地 stage，并且路径前只有一个斜杠。

由索引模型根据 Issue 内容生成。