Payments Block width issue on Template editor

### Impacted plugin

Jetpack

### Quick summary

When the Payments block is used on the Front Page template editor, the width shows correctly on the editor but not on the live site.

### Steps to reproduce

1- Use a block theme (I replicated on twenty twenty four and Bute)
2- Create a Payments block on the Front Page template editor (do not assign an individual page as the homepage)
3- Change button width, for example, make it full-width.
4- Compare looks on editor vs live.

Example of page button displaying on editor:


How it shows live:


### A clear and concise description of what you expected to happen.

For the button to look consistently with the correct width on the live page.

### What actually happened

Live page not showing correctly.

### Impact

Some (< 50%)

### Available workarounds?

Yes, difficult to implement

### Platform (Simple and/or Atomic)

Simple, Atomic

### Logs or notes

Reported on 8533803-zd

Reproduce the Payments block on the Front Page template editor using a block theme such as Twenty Twenty-Four or Bute, then compare its configured button width with the live page. Trace the editor and live rendering entry points and confirm that full-width and other button widths are consistent on both sides.

Written by the indexing model from the issue text.