Undefined constant MAIN_REQUEST

Nobody has claimed this yet.

After upgrading Litespeed from 1.2 to 1.3, I am getting WSOD. Upon checking the logs, I see this:

```
php Error: Undefined constant Drupal\lite_speed_cache\StackMiddleware\LiteSpeedCache::MAIN_REQUEST in
Drupal\lite_speed_cache\StackMiddleware\LiteSpeedCache->handle() (line 109 of...
```

I can see from [this latest commit](https://github.com/litespeedtech/lscache-drupal/commit/47dbd9309ded793c6c91775d4fc8b88b76524c09#diff-fc50bfa67758aba34bb91d53a9c0b01a69ccee7a30415577c99abd5f35e748b9R109) that MAIN_REQUEST is being used instead of MASTER_REQUEST.

MASTER_REQUEST is required for HttpKernelInterface:

```
interface HttpKernelInterface
{
public const MASTER_REQUEST = 1;
public const SUB_REQUEST = 2;

/**
* Handles a Request to convert it to a Response.
*
* When $catch is true, the implementation must catch all exceptions
* and do its best to convert them to a Response instance.
*
* @param int $type The type of the request
* (one of HttpKernelInterface::MASTER_REQUEST or HttpKernelInterface::SUB_REQUEST)
* @param bool $catch Whether to catch exceptions or not
*
* @return Response A Response instance
*
* @throws \Exception When an Exception occurs during processing
*/
public function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true);
}
```

Would be great if this can be fixed asap as I cannot use Litespeed anymore. I'll need to revert to 1.2 for now.

Start with Drupal\lite_speed_cache\StackMiddleware\LiteSpeedCache->handle() around line 109 and compare the latest commit linked in the issue with the HttpKernelInterface constants shown here. Done means the middleware no longer raises the undefined MAIN_REQUEST error after upgrading to LiteSpeed 1.3.

Written by the indexing model from the issue text.