fix(ScrollView): fix SectionList jumping when sticky headers are enabled fix(ScrollView): forward onCellLayout in ScrollViewStickyHeader

[Aditya31032006]

Summary:

Fixes #58925

What's the problem?

When scrolling through a long SectionList with sticky headers turned on (stickySectionHeadersEnabled), the list starts glitching and rapidly jumping back and forth between rows once you scroll down a bit.

Why does this happen?

1. When a header becomes sticky, ScrollViewStickyHeader wraps it inside a container.
2. It is supposed to handle measuring the header's position and pass that measurement along to the list. To do this, it removes onLayout from the child so the child doesn't measure itself.
3. However, VirtualizedList (which powers SectionList) doesn't use onLayout—it uses onCellLayout.
4. Because ScrollViewStickyHeader only looked for onLayout, the list item kept its own measurement listener.
5. Inside the wrapper, the item measured its position as y = 0 (relative to the sticky wrapper) instead of where it actually is on the screen.
6. The list stored 0 as the item's position, got confused about where rows should go, and started jumping back and forth.

What is the fix?

• In ScrollViewStickyHeader, we now also check for onCellLayout and forward the measurement to it.
• We clear onCellLayout on the child component so it doesn't accidentally measure y = 0.
• Updated the comments in VirtualizedListCellRenderer to describe this behavior accurately.

Changelog:

[GENERAL] [FIXED] - Fix SectionList jumping/shaking when sticky headers are enabled

Test Plan:

1. Create a SectionList with many items and stickySectionHeadersEnabled={true}.
2. Scroll down past a few headers.
3. Before: The list shakes/jumps back and forth between two sets of rows.
4. After: The list scrolls smoothly with no jumping or flickering.

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