Enable custom field configuration for to-dos in release templates

When creating to-dos within a release template, only Title, Description, and Assigned To fields can be configured. Custom fields cannot be set in the template, requiring manual updates to custom field values every time a release is created from the template.

Release templates with to-dos are used to track cross-functional go-to-market activities across multiple functional teams. A "Functional Team" custom field has been added to to-dos to enable filtered reports showing each team their upcoming work. Without the ability to pre-set custom field values in the template, significant time is spent manually updating these fields for every release, and there is risk of inconsistent data entry across releases.

Allow all to-do fields - including custom fields - to be configurable within release templates. When configuring a to-do in a release template phase, users should be able to set values for custom fields in the same way Title, Description, and Assigned To can be set. When a release is created from the template, all to-dos would include their configured custom field values without requiring manual updates.