fix: correct oldestL1Origin comparison logic

[hawkadrian]

Fix incorrect comparison in oldestL1Origin update. Changed from comparing with latestL1Origin to comparing with oldestL1Origin itself, matching the logic used for oldestL2 tracking.

[tynes]

We cannot accept this change without unit test coverage showing that it is a bug

[opgitgovernance]

This pr has been automatically marked as stale and will be closed in 5 days if no updates

[hawkadrian]

hey @sebastianst, please check out my changes, provided tests as asked