Product Gallery block: Add setting to control the appearance of the next/prev buttons

[thealexandrelara]

Description

The Product Gallery block is expected to have a setting to control the appearance of the Next / Previous buttons.

Outcomes

New setting:

• Next/Prev buttons setting in the Inspector Controls

Acceptance criteria

• The setting appears in the Inspector Controls inside a section called Next/Prev buttons
• The setting contains 3 options that can be selected:
  • No next or previous buttons should be displayed
  • Next and previous buttons will appear on outside the large image
  • Next and previous buttons will appear within the large image
• When selecting an option, the change should immediately be reflect on the Editor
• When selecting an option and saving the post/page/template, the change should be reflected on the frontend

[thealexandrelara]

Completed in #10235