test(Sharing): Fix tests on 32-bits

Signed-off-by: provokateurin <kate@provokateurin.de>

Author: provokateurin

tests/lib/Sharing/AbstractSharingManagerTests.php

@@ -140,8 +140,8 @@ abstract protected function getShares(
 	protected IFactory $l10nFactory;
 
 	private function parseTime(mixed $timestampMs): \DateTimeImmutable {
-		$timestampMs = (int)$timestampMs;
-		$time = \DateTimeImmutable::createFromFormat('U.u', number_format((float)$timestampMs / 1000.0, 3, '.', ''));
+		$timestampMs = (float)$timestampMs;
+		$time = \DateTimeImmutable::createFromFormat('U.u', number_format($timestampMs / 1000.0, 3, '.', ''));
 		if ($time === false) {
 			throw new \RuntimeException('invalid timestamp: ' . $timestampMs);
 		}