SEPA direct debit payments now consistently use the recurring payment status instead of marking initial payments separately. This aligns payment files with current banking rules and helps avoid unnecessary processing differences for French direct debit transactions.

## The issue:
'FRST' is the code use for the first transaction. Every following
transaction should have the code 'RCUR'.
Moreover, since 2016, 'FRST' isn't even required anymore.

## The fix:
Simply replace 'FRST' by 'RCUR'

### Ticket: \#2490238

Payslip creation now prevents users from selecting a cancelled employee contract, even when the payslip dates would otherwise match it. This helps payroll teams avoid processing pay based on invalid contracts and reduces the risk of payroll mistakes.

Currently, when creating a payslip, if the dates allow it, you can
select a cancelled contract to base your payslip on. This shouldn't be
the case.

Task ID: 2501310