[Bugfix] 4.2.3 - Update grace days on subscription renew

[lucasdotvin]

This pull request includes changes to the Subscription model and its corresponding tests to handle the grace_days feature more effectively. The most important changes include updating the renew method in Subscription to set the grace_days_ended_at attribute and adding tests to ensure this functionality works correctly.

Enhancements to Subscription model:

• src/Models/Subscription.php: Updated the renew method to set the grace_days_ended_at attribute based on the plan's grace_days value.

Tests for grace_days feature:

• tests/Models/SubscriptionTest.php: Added testModelUpdatesGraceDaysEndedAtWhenRenewing to verify that grace_days_ended_at is correctly updated when renewing a subscription.
• tests/Models/SubscriptionTest.php: Added testModelLeavesGraceDaysEmptyWhenRenewingIfPlanDoesNotHaveIt to ensure grace_days_ended_at remains null if the plan does not have grace days.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.89%. Comparing base (8748602) to head (262ca23).
Report is 2 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #119      +/-   ##
============================================
+ Coverage     97.84%   97.89%   +0.04%     
- Complexity      152      154       +2     
============================================
  Files            26       26              
  Lines           511      522      +11     
============================================
+ Hits            500      511      +11     
  Misses           11       11              

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