Make IxContent top padding configurable to allow full-height children

[prabhjot-brightly]

Prerequisites

• I have read the Contributing Guidelines.
• I have not leaked any internal/restricted information like screenshots, videos, code snippets, links etc.

Suggestion / feature request

Use Case / Problem:
In applications where full-height content is required (e.g., dashboards, data tables, or embedded apps), the fixed top padding prevents proper stretching once we remove it using padding top :0 then child doesn't get stretched

Proposed Solution / Feature Request:

Make the top padding of IxContent configurable via a prop or CSS variable.

Ensure that child content can take full height even when padding is removed.

Benefit:

Gives developers more flexibility to build full-height layouts.

Avoids layout hacks and improves usability of IxContent in custom applications.