Function validate_read_then_write_dependencies 

pub(crate) fn validate_read_then_write_dependencies(
    catalog: &Catalog,
    id: &CatalogItemId,
) -> Result<(), AdapterError>

Validates that all dependencies are valid for read-then-write operations.

Ensures all objects the selection depends on are valid for ReadThenWrite operations:

• They do not refer to any objects whose notion of time moves differently than that of user tables. This limitation is meant to ensure no writes occur between this read and the subsequent write.
• They do not use mz_now(), whose time produced during read will differ from the write timestamp.