fix(jobs): restore background_jobs_expiration_days behavior

Snowflake ID in `JobRuns:deleteBefore()` is computed from given
timestamp, but immediately overwritten by a literal value making the
expiration setting have no effect.

This looks like a leftover artifact from development that should be
cleaned up. Remove the hardcoded ID to restore the desired behavior.

Fixes: dc5499a
Suggested-by: Michele Marcionelli
Signed-off-by: Stefan Kalscheuer <stefan@stklcode.de>

Author: stklcode

lib/private/BackgroundJob/JobRuns.php

@@ -63,7 +63,6 @@ public function finished(int|string $runId, int $duration, int $memoryPeakUsage,
 
 	public function deleteBefore(int $timestamp): int {
 		$beforeSnowflake = $this->snowflakeGenerator->minForTimeId($timestamp);
-		$beforeSnowflake = '91480652934574081';
 		$qb = $this->connection->getQueryBuilder();
 		$result = $qb
 			->delete(self::TABLE)