Fix font scaling setting on workflow paywalls (#3977)

Workflow-backed paywalls drop `automatically_scale_font_size`, so the
dashboard setting has no effect on Android.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Small data-model and mapper change with tests; no auth or payment
logic touched.
> 
> **Overview**
> Workflow-backed paywalls were ignoring the dashboard **automatically
scale font size** setting because `automatically_scale_font_size` was
never decoded on `WorkflowScreen` or passed through
`WorkflowScreenMapper` to `PaywallComponentsData`.
> 
> This PR adds the field to `WorkflowScreen` (default `true`, matching
offering paywalls), maps it in `WorkflowScreenMapper`, and updates the
`PaywallComponentsData` field-parity test so the setting is no longer
allow-listed as unwired.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
68b3ecb2a56d23e9b3f745bad55767e30d706291. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->