[10.x] Fix Http::retry so that throw is respected for call signature Http::retry([1,2], throw: false)

[paulyoungnb]

Http::retry accepts the first parameter for times as an array|int. The documentation states that:

If all of the requests fail, an instance of Illuminate\Http\Client\RequestException will be thrown. If you would like to disable this behavior, you may provide a throw argument with a value of false.

However an Illuminate\Http\Client\RequestException is thrown as can be seen by adding a test to HttpClientTest:

public function testRequestExceptionIsNotThrownWhenDisabledAndRetriesExhaustedWithBackoffArray()
{
    $this->factory->fake([
        '*' => $this->factory->response(['error'], 403),
    ]);

    $response = $this->factory
        ->retry([1,2], throw: false)
        ->get('http://foo.com/get');

    $this->assertTrue($response->failed());

    $this->factory->assertSentCount(3);
}

Other tests have just been added to cover usage of the first parameter as an array.

This issue is due to PendingRequest.php:927 and PendingRequest.php:931 where the following comparisons are used:

if ($attempt < $this->tries && $shouldRetry) {
if ($this->tries > 1 && $this->retryThrow) {

even though $this->tries is an array. Suggested fix from this PR is to use:

$tryCount = is_array($this->tries) ? count($this->tries) + 1 : $this->tries;

in place of $this->tries. The count($this->tries) + 1 is required as specifying the retries in an array already assumes that the first request has been made and that the backoff times specified will be used. Whereas specifying the number of tries assumes that it includes the first request.