Allow updating PT and PE upper to 1 year if data_inicio is below the cutoff

[edulauer]

Fix #223
Allow update PT and PE upper to 1 year if data_inicio below the cutoff
Changes

• Allow updating Plano de Trabalho (PT) and Plano de Entregas (PE) upper to 1 year when data_inicio is earlier than the cutoff date.
• New constant PT_PE_UPDATE_YEAR_VALIDATION_CUTOFF_DATE set to 2025-05-31.
• Moved over_a_year validation logic from Pydantic to the API layer.
• Created tests for updating Plano de Entregas.
• Adjust tests for updating Plano de Trabalho based on the cutoff date