remove deprecated/broken OptionsWithFallback#unique_type

[zvkemp]

When enqueuing a job, the client middleware continues to viewsidekiq_options unique: :until_executed as valid, and inserts a lock for the job. However, the Locksmith does not look at the deprecated unique_type method (only the LOCK key), so when running the lock.lua script, the conditional that should unlock upon completion (if lock == "until_expired" and ttl then ...) is never executed.

Discovered on version 6.0.15 (earlier 6.0.x releases have this issue as well edit: appears to have been introduced in 6.0.15), and though 7.0.0.beta2 has been considerably refactored, it still appears to be an issue.

Given that unique was deprecated as of 6.0 in favor of lock, it seems best to remove it entirely.

[mhenrixon]

Yup, it should totally be removed for v7! Thank you for your contribution 👍

[mhenrixon]

Thanks a bunch for the contribution! I will backport the fix for v6