LightSpeed Cache comment should be omitted in special case

As noted by @milindmore22 in https://github.com/litespeedtech/lscache_wp/issues/212#issuecomment-2569443269, a lot of support topics still involve the LightSpeed Cache comment. While waiting for the issue to be fixed upstream, we should be able to resolve it by adding the following (h/t @szepeviktor in https://github.com/litespeedtech/lscache_wp/issues/212#issuecomment-2569524293):

```php
add_filter( 'litespeed_comment', '__return_false' );
```

Inside this condition:

https://github.com/ampproject/amp-wp/blob/76ab0ae10712638b23568af9bb0ed12c1465600d/includes/validation/class-amp-validation-manager.php#L632-L640

Start at includes/validation/class-amp-validation-manager.php around lines 632-640 and inspect the condition described in the issue. Confirm the LightSpeed-specific filter is applied only in that special case, and verify that the LightSpeed Cache comment is omitted there without changing other validation behavior.

Written by the indexing model from the issue text.