[11.x] Prevent crash when handling ConnectionException in HttpClient retry logic

[shinsenter]

Recently, I have been using HttpClient to crawl some websites in order to extract data for personal purposes. During the crawler monitoring process, I noticed that many errors like the following appear:

  Error 
  Call to undefined method Illuminate\Http\Client\ConnectionException::toException()

  at vendor/laravel/framework/src/Illuminate/Http/Client/PendingRequest.php:1058
    1054▕             return $exception;
    1055▕         }
    1056▕ 
    1057▕         if ($attempt < $this->tries && $shouldRetry) {
  ➜ 1058▕             $options['delay'] = value($this->retryDelay, $attempt, $response->toException());
    1059▕ 
    1060▕             return $this->makePromise($method, $url, $options, $attempt + 1);
    1061▕         }
    1062▕ 

      +14 vendor frames 

After reading through the source code at the error location, I found that when the $response variable is of type ConnectionException, an error occurs at line 1058 because there is no toException() method defined in the ConnectionException class.

framework/src/Illuminate/Http/Client/PendingRequest.php

Line 1058 in 53a5aab

$options['delay'] = value($this->retryDelay, $attempt, $response->toException());

This pull request will add a condition to check the data type of the $response variable before passing it as a parameter to the value() function. This approach is similar to other locations within the same handlePromiseResponse() function where the value is being used, so I think it will not affect other functionalities.

I would appreciate if you could review and merge this patch.

[driesvints]

Heya! We were having some failures in the testsuite at the base branch. Could you rebase this PR, make sure tests pass and mark for review again? Thanks!