Refactored and streamlined the handling of financial transactions, invoices, and installment logic in `InstitutionContractApplication` and `InstitutionContractRepository`. Removed redundant code and consolidated logic for creating financial transactions and invoices into a reusable structure.
- Delegated financial transaction and invoice creation to the application layer.
- Simplified installment handling by directly managing installment lists.
- Introduced modular logic for handling installment and full payment scenarios.
- Replaced redundant `FinancialInvoice` and `FinancialInvoiceItem` creation in the repository layer.
- Added logic to retrieve `financialStatement` from the repository when available.
- Improved consistency in handling `invoiceAmount` across payment-related operations.
- Removed unused code for unpaid invoice retrieval and associated logic.
- Added support for creating `CreateContactInfo` objects for institution contracts.
These changes improve code maintainability, readability, and modularity by reducing duplication and ensuring responsibilities are handled at the appropriate layers.