FINERACT-2910: Fix stale installment interest after add-charge and undo-waive when external events are disabled

[galovics]

Description

FINERACT-2910: with external events disabled, the stored interest/principal split of a progressive (advanced payment allocation) loan installment is stale after add-charge or undo-waive-charge, while it is correct with events enabled.

Root cause: when the loan event is serialized in BusinessEventNotifierServiceImpl.beforeCommit, LoanBusinessEventSerializer -> ProgressiveLoanSummaryDataProvider -> InterestScheduleModelRepositoryWrapperImpl.getSavedModel recalculates the interest schedule model and writes it onto the managed installments, which are flushed on commit. The add-charge path skips reprocessing when the charge is due after the last transaction, and undo-waive never reprocesses, so those two commands only got fresh installments as a side effect of event serialization.

Fix: after the add-charge reprocess-skipped branch and after undo-waive, call the existing ReprocessLoanTransactionsService.updateModel, guarded to progressive, interest-bearing loans with interest recalculation that are not matured (the same conditions under which serialization recalculates). Persisted state no longer depends on event posting.

Not changed: making event serialization / getSavedModel side-effect free (it also affects accruals, prepayment and the investor interest calculation, and would change persisted values for events-enabled deployments). That should be a separate change.

Tests: new LoanChargeInterestRecalculationTest, run with the LoanBalanceChangedBusinessEvent type enabled and disabled. Verified failing without the fix (0.39 instead of 0.42) and passing with it, with FINERACT_EXTERNAL_EVENTS_ENABLED both false and true. The e2e scenarios from the ticket (C4311, UC15) and the full LoanReAmortization-Part1 and LoanDelayedScheduleCaptures-Part1 features pass with events off and on.

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[adamsaghy]

LGTM