Add test for 0 and '0' in PeriodicalTrigger

Fix '0' case error and remove duplicate code

Author: ardentsword

src/Symfony/Component/Scheduler/Tests/Trigger/PeriodicalTriggerTest.php

@@ -73,6 +73,8 @@ public static function getInvalidIntervals(): iterable
         yield ['3600.5'];
         yield ['-3600'];
         yield [-3600];
+        yield ['0'];
+        yield [0];
     }
 
     /**

src/Symfony/Component/Scheduler/Trigger/PeriodicalTrigger.php

@@ -30,18 +30,11 @@ public function __construct(
         $this->from = \is_string($from) ? new \DateTimeImmutable($from) : $from;
         $this->until = \is_string($until) ? new \DateTimeImmutable($until) : $until;
 
-        if (\is_int($interval) || \is_float($interval)) {
-            if (0 >= $interval) {
+        if (\is_int($interval) || \is_float($interval) || \is_string($interval) && ctype_digit($interval)) {
+            if (0 >= (int) $interval) {
                 throw new InvalidArgumentException('The "$interval" argument must be greater than zero.');
             }
 
-            $this->intervalInSeconds = $interval;
-            $this->description = sprintf('every %d seconds', $this->intervalInSeconds);
-
-            return;
-        }
-
-        if (\is_string($interval) && ctype_digit($interval)) {
             $this->intervalInSeconds = (int) $interval;
             $this->description = sprintf('every %d seconds', $this->intervalInSeconds);