bug: commented out env variables cause app to fail to boot

### Current Behavior

There is a bug that started happening in v3.17.0.

I have a few commented out environment variables using the syntax `${{MY_ENV_VAR}}`. It appears something is attempting to resolve those, even though commented out.

It should not be resolving env vars from commented out lines.
```ansii
/usr/local/openrestv//luajit/bin/luajit ./apisix/cli/apisix.lua init
failed to read local vaml config of apisix: failed to handle configuration: can't find environment variable MY_ENV_VAR
```

The routes files contains:

```yaml
# ${{MY_ENV_VAR}}
```

### Expected Behavior

The app should start without weeping due to commented out environment variables.

### Error Logs

_No response_

### Steps to Reproduce

See above.

### Environment

From helm chart v2.16.0 = APISix 3.17.0.