[Python] Disable PyExtensionType autoload #38607
Description
Describe the bug, including details regarding any error messages, version, and platform.
PyExtensionType autoload is really a misfeature. It creates Python-specific extension types and using ExtensionType is almost the same complexity.
We should therefore disable PyExtensionType autoloading and deprecate PyExtensionType instantiation.
Component(s)
Python