redis store sometimes returns $contents without key expires_at

[jmglsn]

Hey,

I noticed that under some circumstances the array $contents is missing the key expires_at right over here:

https://github.com/ankitpokhrel/tus-php/blob/f50852b85b513ec5589f7871d4ca59d7c1c3ad8d/src/Cache/RedisStore.php#L60

It's showing up super seldom but maybe worth a short investigation.

Thank you!