Allow API/MCP pricing updates when Dynamic Pricing is enabled

Currently, attempting to update property pricing via the API or MCP while Dynamic Pricing is enabled results in an error stating that updates cannot be made. However, in the Hospitable UI, users can manually override specific dates even with Dynamic Pricing on. This request is to bring the API/MCP functionality in line with the UI, allowing for manual price overrides via the API regardless of the Dynamic Pricing status.