Previously the canInsertNativeNode and getRenderParent functions had almost
_exaclty_ the same logic. What was worse that getRenderParent was calling
canInsertNativeNode thus executing the same, non-trivial logic twice.
This commit merges canInsertNativeNode and getRenderParent into one function.
Now getRenderParent will return a native parent or null if a node can't be
inserted (content projection, root of a view that is not inserted etc.).
PR Close#28011