Nested clipping with RTT does not work

[wouterlucas]

When nodes are nested with multiple layers of clipping and the parent node enables RTT the children clipping regions are ignored.

Eg:

- Node (RTT: true)
    - Child 1
    - Child 2 (clipping: True)
        - SubChild 2.1
        - SubChild 2.2
    - Child 3 

In this case SubChild 2.1 and SubChild 2.2 do not receive a proper clipping area.

The issue sits here:
https://github.com/lightning-js/renderer/blob/main/src/core/CoreNode.ts#L1139

Currently once RTT is enabled it ignores clipping regions for children. This is fine and needed because else you'd be enabling clipping on a sub region on a texture that is misaligned but does not take children into account who have clipping enabled.

What we need to change is:

• Check if a child or a RTT node has clipping enabled
• Honor clipping region if enabled per local RTT matrix