feat: redocly scroll y offset

[melissag-ensemble]

Description

Enable scrollYOffset config so user can adjust the top of the redocly page so that it doesn't overlap with the top nav.

Related Issue

https://jira.corp.adobe.com/browse/DEVSITE-1347
https://jira.corp.adobe.com/browse/DEVSITE-1308

Motivation and Context

Slack conversation: https://adobeio.slack.com/archives/C01GU3V8XE0/p1727220077882769

This serves two purposes:

• provide a quick fix for https://jira.corp.adobe.com/browse/DEVSITE-1347, while we haven't migrated to the next gen yet (where we're using layout grid, which better addresses the issue)
• fulfill request in https://jira.corp.adobe.com/browse/DEVSITE-1308 to add more configs to RedoclyAPIBlock so to retain same look and feel when migrating from portal to on-premise-license version

How Has This Been Tested?

Page: https://developer-stage.adobe.com/redocly-test/api-full/#operation/getInventory
Src: AdobeDocs/redocly-test@29aa4d5#diff-ebd9ea94b0769347dd6343596cd0a667cbe2004d8c7a3cd952c4ae6d055f69d7R3

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.