Feat(portal): add conditional database fields in UI for advanced node.js template

[VH3956]

Description: This PR implements the dynamic form logic for the Backstage scaffolder wizard to improve Developer Experience. It uses react-jsonschema-form (RJSF) conditional logic (dependencies) to only show database configuration fields when the user explicitly requests a database, closing the Issue #36 and the Dynamic Wizard design document.

Changes Made:

1. Updated Template Schema (apps/portal/examples/advanced-template/template.yaml):

   • Added a new "Database Configuration" step.

   • Added a mock requireDatabase checkbox (anticipating Issue [Setup] Scaffold Dynamic Wizard Extension #35).

   • Implemented JSON Schema dependencies logic tied to the requireDatabase checkbox.

   • Conditionally rendered fields:

     • databaseType: Select dropdown (defaults to postgres).

     • databaseName: Text input.

     • databaseVersion: Select dropdown (13, 14, 15, 16 - defaults to 15).

   • Added validation to ensure conditionally shown fields are marked as required only when visible.

Testing Instructions: apps/portal

1. yarn install + yarn start

2. Go to the Create tabs

3. Select the Advanced Node.js Template (GitOps + Webhooks).

4. Fill out the "Component Information" step and click Next.

5. On the "Database Configuration" step:

   • Verify Hide: Ensure only the "Add Database" checkbox is visible by default. You should be able to proceed without validation errors.

   • Verify Show: Check the "Add Database" box. The Database Type, Database Name, and Database Version fields should instantly appear.

   • Verify Validation: With the box checked, leave Database Name blank and attempt to click "Next". The form should block you and display a required field error.

   • Verify Reset: Uncheck the box. The fields should disappear, and the validation error should clear.

⚠️ Note for the Issue #35 (Add Database Checkbox):

The global checkbox component in Issue #35:To make sure our UI logic wires up correctly, please ensure the boolean property name for the checkbox in the final schema is named exactly requireDatabase.

If you decide to use a different property name (e.g., hasDatabase, addDb), please let me know so I can update the dependencies mapping in template.yaml to match your variable name, or feel free to update the dependency key in this template yourself when you merge!