Two bug fixes on the schedule mechanism for requeueing

[anero]

This PR fixes a couple of bugs found while testing the new schedule mechanism for putting back jobs on the queue:

• Fixed a bug on how the maximum retry period is calculated from strategies in StrategyCollection
• Fixed how the call to re-queue a job is made, to only include the "queue:" prefix if needed (when performing a direct lpush on redis). This otherwise caused new queues to be created with the extra prefix.

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 98.71%. Comparing base (a15db1b) to head (7465a83).

Files with missing lines	Patch %	Lines
lib/sidekiq/throttled/strategy.rb	80.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #201   +/-   ##
=======================================
  Coverage   98.71%   98.71%           
=======================================
  Files          19       19           
  Lines         466      468    +2     
  Branches       77       77           
=======================================
+ Hits          460      462    +2     
  Misses          6        6           

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[mnovelo]

@anero created a PR with a minor suggestion controlshift#6

[anero]

@mnovelo Thank you! I merged your changes.

@ixti This is ready for reviewing.