Make $validator arg in AgaviValidationIncident::__construct() optional

[thomasbachem]

No description provided.

[ddelbondio]

could you please provide a use case for this? (i know we discussed this, but i can't remember what it was)

[thomasbachem]

It had something to do with manually triggering validation errors, e.g. with

$incident = new AgaviValidationIncident(null);
$incident->addError(new AgaviValidationError($message, $index, $affectedArguments));

$report = $this->getContainer()->getValidationManager()->getReport();
foreach($affectedArguments as $argument) {
    $report->addArgumentResult($argument, $severity);
}
$report->addIncident($incident);

But it's mostly a cosmetic improvement.